Active and Passive Voice

The active voice (where the verb's subject is understood to denote the doer, or agent), of the denoted action) is the unmarked voice in English.

To form the passive voice (where the subject denotes the undergoer, or patient), of the action), a periphrastic construction is used.

In the canonical form of the passive, a form of the auxiliary verb be (or sometimes get) is used, together with the past participle of the lexical verb. Passive voice can be expressed in combination together with tenses, aspects and moods, by means of appropriate marking of the auxiliary (which for this purpose is not a stative verb, i.e. it has progressive forms available).

For example:

• This room is tidied regularly. (simple present passive)
• It had already been accepted. (past perfect passive)
• Dinner is being cooked right now. (present progressive passive)

The passive forms of certain of the combinations involving the progressive aspect are quite rare; these include the present perfect progressive (it has been being written), past perfect progressive (it had been being written), future progressive (it will be being written), future perfect progressive (it will have been being written), conditional progressive (it would be being written) and conditional perfect progressive (it would have been being written). Because of the awkwardness of these constructions, they may be paraphrased, for example using the expression in the process of (it has been in the process of being written, it will be in the process of being written, and similar).

The uses of these various passive forms are analogous to those of the corresponding tense–aspect–mood combinations in the active voice.

Infinitive

Regarding English, the term infinitive is traditionally applied to the unmarked form of the verb when it forms a non-finite verb, whether or not introduced by the particle to.

Hence sit and to sit, as used in the following sentences, would each be considered an infinitive:

• I can sit here all day.
• I want to sit on the other chair.

The form without to is called the bare infinitive; the form introduced by to is called the full infinitive or to-infinitive.

The other non-finite verb forms in English are the gerund or present participle (the -ing form), and the past participle – these are not considered infinitives.

Moreover, the unmarked form of the verb is not considered an infinitive when it is forms a finite verb: like a present indicative ("I sit every day"), subjunctive ("I suggest that he sit"), or imperative ("Sit down!"). (For some irregular verbs the form of the infinitive coincides additionally with that of the past tense and/or past participle, like in the case of put.)

Certain auxiliary verbs are defective in that they do not have infinitives (or any other non-finite forms).

This applies to the modal verbs (can, must, etc.), as well as certain related auxiliaries like the had of had better and the used of used to. (Periphrases can be employed instead in some cases, like (to) be able to for can, and (to) have to for must.) It also applies to the auxiliary do, like used in questions, negatives and emphasis like described under do-support. Infinitives are negated by simply preceding them with not.

Of course the verb do when forming a main verb can appear in the infinitive. However, the auxiliary verbs have (used to form the perfect) and be (used to form the passive voice and continuous aspect) both commonly appear in the infinitive: "I should have finished by now"; "It's thought to have been a burial site"; "Let him be released"; "I hope to be working tomorrow."

Perfect Infinitive

There are nonfinite constructions that are marked for perfect, progressive or perfect progressive aspect, using the infinitives, participles or gerunds of the appropriate auxiliaries. The meanings are as would be expected for the respective aspects: perfect for prior occurrence, progressive for ongoing occurrence at a particular time. (Passive voice can also be marked in nonfinite constructions – with infinitives, gerunds and present participles – in the expected way: (to) be eaten, being eaten, having been eaten, etc.)

Examples of nonfinite constructions marked for the various aspects are given below.

Bare infinitive:

• You should have left earlier. (perfect infinitive; for similar constructions and their meanings see modal verbs)
• She might be revising. (progressive; refers to an ongoing action at this moment)
• He must have been working hard. (perfect progressive; i.e. I assume he has been working hard)

To-infinitive:

• He is said to have resigned. (perfect infinitive)
• I expect to be sitting here this time tomorrow. (progressive)
• He claims to have been working here for ten weeks. (perfect progressive)

Present participle:

• Having written the letter, she went to bed. (perfect)
• The man having left, we began to talk. (perfect, in a nominative absolute construction)
• Having been standing for several hours, they were beginning to feel tired. (perfect progressive)

Past participle:

• We have been waiting a long time. (progressive, used only as part of a perfect progressive construction)

Gerund:

• My having caught the spider impressed the others. (perfect)
• We are not proud of having been drinking all night. (perfect progressive)

Other aspectual, temporal and modal information can be marked on nonfinite verbs using periphrastic constructions. For example, a "future infinitive" can be constructed using forms such as (to) be going to eat or (to) be about to eat.

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 Future

The term simple future, future simple or future indefinite, as applied to English, generally refers to the combination of the modal auxiliary verb will with the bare infinitive of the main verb.

Sometimes (particularly in more formal or old-fashioned English) shall is preferred to will when the subject is first person (I or we).

The auxiliary is often contracted to _ 'll_.

This construction can be used to indicate what the speaker views as facts about the future, including confident predictions:

• The sun will rise tomorrow at 6:14.
• It will rain later this week.

It may be used to describe future circumstances that are subject to some condition:

• He will go there if he can.

However English also has other ways of referring to future circumstances. For planned or scheduled actions the present progressive or simple present may be used. There is also a going-to future, common in colloquial English, which is often used to express intentions or predictions (I am going to write a book some day; I think that it is going to rain). Use of the will/shall construction when expressing intention often indicates a spontaneous decision:

• I know! I'll use this book as a door stop.

Compare I'm going to use..., which implies that the intention to do so has existed for some time.

Use of present tense rather than future constructions in condition clauses and certain other dependent clauses is described below under and. The modal verbs will and shall also have other uses besides indicating future time reference. For example:

• I will pass this exam. (often expresses determination in addition to futurity)
• You will obey me! (insistence)
• I will not do it! (negative insistence, refusal)
• At this moment I will tolerate no dissent. (strong volition)
• He hasn't eaten all day; he will be hungry now. (confident speculation about the present)
• One of his faults is that he will make trouble unnecessarily. (habit)
• Shall we get to work? (suggestion)

Future Progressive

The future progressive or future continuous combines progressive aspect with future time reference; it is formed with the auxiliary will (or shall in the first person, the bare infinitive be, and the present participle of the main verb.

It is used mainly to indicate that an event will be in progress at a particular point in the future:

• This time tomorrow I will be taking my driving test.
• I imagine we will already be eating when you arrive.

The usual restrictions apply, on the use both of the future and of the progressive: simple rather than progressive aspect is used with some stative verbs, and present rather than future constructions are used in many dependent clauses. The same construction may occur when will or shall is given one of its other uses, for example:

• He will be sitting in his study at this time. (confident speculation about the present)

Future Perfect

The future perfect combines aspect with future time reference.

It consists of the auxiliary will (or sometimes shall in the first person, as above), the bare infinitive have, and the past participle of the main verb.

It indicates an action that is to be completed sometime prior to a future time of perspective, or an ongoing action continuing up to a future time of perspective (compare uses of the present perfect above).

• I shall have finished my essay by Thursday.
• When I finally search him he will have disposed of the evidence.
• By next year we will have lived in this house for half a century.

For the use of the present tense rather than future constructions in certain dependent clauses.

The same construction may occur when will or shall is given one of its other meanings; for example:

• He will have had his tea by now. (confident speculation about the present)
• You will have completed this task by the time I return, is that understood? (giving instruction)

Future Perfect Progressive

The future perfect progressive or future perfect continuous combines perfect progressive aspect with future time reference.

It is formed by combining the auxiliary will (or sometimes shall, as above), the bare infinitive have, the past participle been, and the present participle of the main verb.

Uses of the future perfect progressive are analogous to those of the present perfect progressive, except that the point of reference is in the future. For example:

• He will be very tired because he will have been working all morning.
• By 6 o'clock we will have been drinking for ten hours.

For the use of present tense in place of future constructions in certain dependent clauses.

The same construction may occur when the auxiliary (usually will) has one of its other meanings, particularly expressing a confident assumption about the present:

• No chance of finding him sober now; he*'ll have been drinking* all day.

Indirect Speech

Verbs often undergo tense changes in indirect speech. This commonly occurs in content clauses (typically that-clauses and indirect questions, when governed by a predicate of saying (thinking, knowing, etc.) which is in the past tense or conditional mood.

In this situation the following tense and aspect changes occur relative to the original words.

Changes to past:

• "I like apples." → He said that he liked apples.
• "We are riding." → They claimed that they were riding.
• "You have sinned." → I was told that I had sinned.

Changes to past perfect (and sometimes past progressive to past perfect progressive):

• "They finished all the wine earlier." → He thought they had finished all the wine earlier.

This change does not normally apply, however, when the past tense is used to denote an unreal rather than a past circumstance (e.g., expressions of wish, conditional sentences and dependent clauses):

• "I would do anything you asked." → He said he would do anything she asked.

Changes to conditional, also referred to as future-in-the-past (i.e. will/shall changes to would/should):

• "The match will end in a draw." → He predicted that the match would end in a draw.

The modals can and may change to their preterite forms could and might :

• "We may attend." → She told us that they might attend.

Verb forms not covered by any of the above rules (verbs already in the past perfect, or formed with would or other modals not having a preterite equivalent) do not change. Note that application of the above rules is not compulsory; sometimes the original verb tense is retained, particularly when the statement (with the original tense) remains equally valid at the moment of reporting:

• "The earth orbits the sun." → Copernicus stated that the earth orbits the sun.

Note also that the above tense changes do not apply when the verb of saying (etc.) is not past or conditional in form; in particular there are no such changes when that verb is in the present perfect: He has said that he likes apples.

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: Hard

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