Clause

A clause is a grammatical unit built around a verb that typically contains a subject and a predicate. Understanding clauses is essential because they are the core building blocks of every sentence you read, write, or speak.

What makes a clause?

At minimum, a clause needs a verb (the predicate) and, in most cases, a subject — the person or thing the verb says something about. The predicate can also include objects, complements, and modifiers.

• She laughed. — subject (she) + verb (laughed)
• The manager approved the budget yesterday. — subject + verb + object + modifier

Sometimes the subject is left out. This happens regularly in imperative sentences and non-finite clauses:

• Sit down. — no visible subject, but "you" is understood
• Walking home, I noticed the shop was closed. — the -ing clause has no stated subject

Types of clauses

There are two main types:

• Independent clause (also called a main clause) — can stand on its own as a complete sentence. It contains a finite verb.

  • I missed the bus.

• Dependent clause (also called a subordinate clause) — cannot stand alone and needs an independent clause to make sense.

  • Because I overslept — incomplete on its own

Combine them and you get a complex sentence:

• I missed the bus because I overslept.

A simple sentence has one independent clause. More complex sentences combine independent and dependent clauses in various ways.

Quick check: If you can remove a group of words from a sentence and it still has a subject + finite verb and makes sense on its own, that group is likely an independent clause.

Why clauses matter

Recognizing clause boundaries helps you punctuate correctly, avoid run-on sentences, and build more varied, natural-sounding writing. Once you can spot where one clause ends and another begins, sentence structure becomes much easier to manage.

Ready to practice? Try Complex Sentence for the basics, then move on to Complex Sentence: Adverbials or Participle Clauses: Shortening Sentences with -ing and Having + Past Participle to deepen your skills.

Simple

"Simple" forms of verbs are those appearing in constructions not marked for either progressive or perfect aspect (I go, I don't go, I went, I will go, etc., but not I'm going or I have gone).

Simple constructions normally denote a single action (perfective aspect), as in Brutus killed Caesar, a repeated action (habitual aspect), as in I go to school, or a relatively permanent state, as in We live in Dallas. They may also denote a temporary state (imperfective aspect), in the case of stative verbs that do not use progressive forms.

Relative Clause

A relative clause is a kind of subordinate clause that contains the element whose interpretation is provided by an antecedent on which the subordinate clause is grammatically dependent; that is, there is an anaphoric relation between the relativized element in the relative clause and antecedent on which it depends.

Typically, a relative clause modifies a noun or noun phrase, and uses some grammatical device to indicate that one of the arguments within the relative clause has the same referent as that noun or noun phrase. For example, in the sentence *I met a man who wasn't there*, the subordinate clause who wasn't there is a relative clause, since it modifies the noun man, and uses the pronoun who to indicate that the same "man" is referred to within the subordinate clause (in this case, as its subject).

In many European languages, relative clauses are introduced by a special class of pronouns called relative pronouns, such as who in the example just given.

Restrictive and Non-restrictive

Bound relative clauses may or may not be restrictive. Whereas a non-restrictive or non-defining relative clause merely provides supplementary information, a restrictive or defining relative clause modifies the meaning of its head word (restricts its possible referent).

For example:

• *The man who lives in this house has not been seen for days*. This (*who lives in this house*) is a restrictive relative clause, modifying the meaning of man, and essential to the sentence (if the clause were omitted, it would no longer be known which man is being referred to). If the bold part is deleted the remaining part does not provide the sense.
• The mayor, who lives in this house, has not been seen for days. This is a non-restrictive relative clause, since it provides supplementary information about the mayor, but is not essential to the sentence – if the clause were omitted, it would still be known which mayor is meant. If the bold part is deleted the remaining part provides the sense. In speaking it is natural to make slight pauses around non-restrictive clauses, and in English this is shown in writing by commas (as in the examples).

Another difference in English is that only restrictive relative clauses may be introduced with that or use the "zero" relative pronoun. In colloquial speech, a non-restrictive relative clause may have a whole sentence as its antecedent rather than a specific noun phrase; for example:

• *The cat was allowed on the bed, which annoyed the dog*.

Here, the context of the sentence (presumably) indicates that which refers not to the bed or the cat but to the entire proposition expressed in the main clause, namely the circumstance that the cat was allowed on the bed. Such constructions are discouraged in formal usage and in texts written for nonnative speakers because of the potential for ambiguity in parsing; a construction more accepted in formal usage would be The cat's being [or having been] allowed on the bed annoyed the dog.

Finite and Non-Finite

Relative clauses may be either finite clauses (as in the examples above) or non-finite clauses. An example of a non-finite relative clause in English is the infinitive clause on whom to rely, in the sentence "She is the person on whom to rely".

Relative Clauses in English

In English, a relative clause follows the noun it modifies. It is generally indicated by a relative pronoun at the start of the clause, although sometimes simply by word order. If the relative pronoun is the object of the verb in the relative clause, it comes at the beginning of the clause even though it would come at the end of an independent clause ("He is the man whom I saw", not "He is the man I saw whom"). The choice of relative pronoun can be affected by whether the clause modifies a human or non-human noun, by whether the clause is restrictive or not, and by the role (subject, direct object, or the like) of the relative pronoun in the relative clause.

• For a human antecedent, "who", "whom", or "that" is usually used ("He is the person who saw me", "He is the person whom I saw", "He is the person that I saw"). For a non-human antecedent, only "that" or "which" is used.
• For a non-human antecedent in a non-restrictive clause, only "which" is used ("The tree, which fell, is over there"); while either "which" or "that" may be used in a restrictive clause ("The tree which fell is over there", "The tree that fell is over there")—but some styles and prescriptive grammars require the use of "that" in the restrictive context.
• Of the relative pronoun pair "who" and "whom", the subjective case form ("who") is used if it is the subject of the relative clause ("He is the policeman who saw me"); and, in formal usage, the objective case form ("whom") if it is the object of the verb or preposition in the relative clause ("He is the policeman whom I saw", "He is the policeman whom I talked to", "He is the policeman to whom I talked"); but in informal usage "whom" is often replaced by "who".

In English, non-restrictive relative clauses are set off with commas, but restrictive ones are not:

• "I met a man and a woman yesterday. The woman, who had a thick French accent, was very pretty." (non-restrictive—does not narrow down who is being talked about)
• "I met two women yesterday, one with a thick French accent and one with a mild Italian one. The woman who had the thick French accent was very pretty." (restrictive—adds information about who is being referred to)The status of "that" as a relative pronoun is not universally agreed.

Simple Past

The simple past, past simple or past indefinite, sometimes called the preterite, is the basic form of the past tense in Modern English. It is used principally to describe events in the past, although it also has some other uses. Regular English verbs form the simple past in -ed; however there are a few hundred irregular verbs with different forms.

The term "simple" is used to distinguish the syntactical construction whose basic form uses the plain past tense alone, from other past tense constructions which use auxiliaries in combination with participles, such as the past perfect and past progressive.

Formation

Regular verbs form the simple past end*-ed*; however there are a few hundred irregular verbs with different forms. For details see.

Most verbs have a single form of the simple past, independent of the person or number of the subject (there is no addition of -s for the third person singular as in the simple present).

However, the copula verb be has two past tense forms: was for the first and third persons singular, and were in other instances.

The form were can also be used in place of was in conditional clauses and the like; for information on this, see subjunctive.

This is the only case in modern English where a distinction in form is made between the indicative and subjunctive moods in the past tense.

Questions, other clauses requiring inversion, negations with not, and emphatic forms of the simple past use the auxiliary did.

A full list of forms is given below, using the (regular) verb help as an example:

• Basic simple past:
  • I/you/he/she/it/we/they helped
• Expanded (emphatic) simple past:
  • I/you/he/she/it/we/they did help
• Question form:
  • Did I/you/he/she/it/we/they help?
• Negative:
  • I/you/he/she/it/we/they did not (didn't) help
• Negative question:
  • Did I/you/he/she/it/we/they not help? / Didn't I/you/he/she/it/we/they help?

Usage

The simple past is used for a single event (or sequence of such events) in the past, and also for past habitual action:

• He took the money and ran.
• I visited them every day for a year.

It can also refer to a past state:

• I knew how to fight even as a child.

For action that was ongoing at the time referred to, the past progressive is generally used instead (e.g. I was cooking). The same can apply to states, if temporary (e.g. the ball was lying on the sidewalk), but some stative verbs do not generally use the progressive aspect at all, and in these cases the simple past is used even for a temporary state:

• The dog was in its kennel.

However, with verbs of sensing, it is common in such circumstances to use could see in place of saw, could hear in place of heard, etc.

• I felt cold.

If one action interrupts another, then it is usual for the interrupted (ongoing) action to be expressed with the past progressive, and the action that interrupted it to be in the simple past:

• Your mother called while you were cooking.

The simple past is often close in meaning to the present perfect.

The simple past is used when the event happened at a particular time in the past, or during a period which ended in the past (i.e. a period that does not last up until the present time).

This time frame may be explicitly stated, or implicit in the context (for example the past tense is often used when describing a sequence of past events).

• I was born in 1980.
• We turned the oven off two minutes ago.
• I came home at 6 o'clock.
• When did they get married?
• We wrote two letters this morning.
• She placed the letter on the table, sighed, and left the house.Contrast these examples with those given at.

Note also that for past actions that occurred before the relevant past time frame, the past perfect is used.

Various compound constructions exist for denoting past habitual action.

The sentence When I was young, I played football every Saturday might alternatively be phrased using used to (... I used to play ...) or using would (... I would play...).

The simple past also has some uses in which it does not refer to a past time.

• If he walked faster, he would get home earlier.
• I wish I knew what his name was.

These are generally in condition clauses and some other dependent clauses referring to hypothetical circumstances, as well as certain expressions of wish:

• He said he wanted to go on the slide.

Past Progressive

The past progressive or past continuous construction combines progressive aspect with past tense, and is formed using the past tense of be (was or were) with the present participle of the main verb.

It indicates an action that was ongoing at the past time being considered:

• At three o'clock yesterday, I was working in the garden. For stative verbs that do not use the progressive aspect, the simple past is used instead (At three o'clock yesterday we were in the garden).

The past progressive is often used to denote an action that was interrupted by an event, or for two actions taking place in parallel:

• While I was washing the dishes, I heard a loud noise.
• While you were washing the dishes, Sue was walking the dog.(Interrupted actions in the past can also sometimes be denoted using the past perfect progressive.)

The past progressive can also be used to refer to past action that occurred over a range of time and is viewed as an ongoing situation:

• I was working in the garden all day yesterday. That could also be expressed using the simple past, as I worked..., which implies that the action is viewed as a unitary event (although the effective meaning is not very different).

Past Perfect

The past perfect, sometimes called the pluperfect, combines past tense with perfect aspect; it is formed by combining had (the past tense of the auxiliary have) with the past participle of the main verb.

It is used when referring to an event that took place prior to the time frame being considered.

This time frame may be stated explicitly, as a stated time or the time of another past action:

• We had finished the job by 2 o'clock.
• He had already left when we arrived.

The time frame may also be understood implicitly from the previous or later context:

• I was eating ... I had invited Jim to the meal but he was unable to attend. (i.e. I invited him before I started eating)
• I had lost my way. (i.e. this happened prior to the time of the past events I am describing or am about to describe)

Compare He had left when we arrived (where his leaving preceded our arrival), with the form with the simple past, He left when we arrived (where his leaving was concurrent with or shortly after our arrival).

Note that unlike the present perfect, the past perfect can readily be used with an adverb specifying a past time frame for the occurrence.

For example, while it is incorrect to say I have done it last Friday (the use of last Friday, specifying the past time, would require the simple past rather than the present perfect), there is no such objection to a sentence like "I had done it the previous Friday".

The past perfect can also be used for states or repeated occurrences pertaining over a period up to a time in the past, particularly in stating "for how long" or since when". However, if the state is temporary and the verb can be used in the progressive aspect, the past perfect progressive would normally be used instead. Some examples with the plain past perfect:

• I had lived in that house for 10 years.
• The children had been in their room since lunchtime.

Past Perfect Progressive

The past perfect progressive or past perfect continuous (also known as the pluperfect progressive or pluperfect continuous) combines perfect progressive aspect with past tense.

It is formed by combining had (the past tense of auxiliary have), been (the past participle of be), and the present participle of the main verb.

Uses of the past perfect progressive are analogous to those of the present perfect progressive, except that the point of reference is in the past.

For example:

• I was tired because I had been running.
• By yesterday morning they had already been working for twelve hours.
• Among the witnesses was John Smith, who had been staying at the hotel since July 10.

This form is sometimes used for actions in the past that were interrupted by some event (compare the use of the past progressive as given above).

For example:

• I had been working on my novel when she entered the room to talk to me.

This implies that I stopped working when she came in (or had already stopped a short time before); the plain past progressive (I was working...) would not necessarily carry this implication.

If the verb in question does not use the progressive aspect, then the plain past perfect is used instead.

The past perfect progressive may also have additional specific uses similar to those of the plain past perfect.

B2 | Upper Intermediate

B2, or Upper Intermediate, is the fourth level on the CEFR scale. It marks the point where you move from "getting by" to genuinely comfortable communication — handling complex topics, expressing nuanced opinions, and understanding most of what you read or hear in real-world contexts.

What a B2 user can do

At this level, you're expected to:

• Understand complex texts on both concrete and abstract topics, including technical discussions in your own field.
• Follow extended speech and lectures, even when the structure isn't entirely clear, as long as the topic is reasonably familiar.
• Interact fluently and spontaneously enough that conversations with native speakers flow naturally — without strain on either side.
• Produce clear, detailed text on a wide range of subjects, using connectors and cohesive devices to build well-structured arguments.
• Explain and defend a viewpoint on a topical issue, weighing the advantages and disadvantages of different options.
• Recognize implicit meaning — reading between the lines in demanding, longer texts.

What B2 grammar looks like in practice

B2 is where grammar stops being about isolated rules and starts being about flexibility and precision. You're expected to control structures like:

• Advanced conditionals and mixed conditionals — moving beyond simple if-clauses to express hypothetical and counterfactual meaning.
• Passive voice in varied tenses and contexts, not just present and past simple.
• Reported speech with correct sequence of tenses, including backshifting and reporting verbs.
• Participle clauses and the distinction between participles and gerunds.
• Comparative and superlative structures beyond basic -er/-est, including double comparatives and qualifying expressions.

Errors still happen at B2, but they rarely cause misunderstanding. The goal is controlled, flexible use of language across social, academic, and professional settings.

How B2 fits in the CEFR progression

B2 builds directly on the foundations of B1 (Intermediate) and prepares you for C1 (Advanced). Many university entrance exams, professional certifications, and immigration requirements target B2 as the minimum standard.

Self-check: If you can read a newspaper editorial, follow most of a TED talk without subtitles, and write a clear essay arguing a position — you're likely operating at B2.

Ready to test yourself? Try Is your English level B2/Upper Intermediate? or practise specific B2 grammar with challenges like Basics. Advanced Conditionals And "wish", Basics. Passive Voice, and Sequence of Tenses in Indirect Speech.

Difficulty: Medium

Medium difficulty. Difficulty levels represent author's opinion about how hard a question or challenge is.