Verb

A verb is a word that expresses an action, a state, or an occurrence — and it's the engine of every English sentence. Understanding how verbs work is foundational to everything else in English grammar, from forming questions to building complex sentences.

Verb Forms

Most English verbs have five inflected forms:

• Base form (go, write, climb) — used as an infinitive, imperative, present subjunctive, and present indicative in all persons except third-person singular.
• -s form (goes, writes, climbs) — used for the present tense, third-person singular (she writes).
• Past tense (went, wrote, climbed) — also called the preterite.
• Past participle (gone, written, climbed) — identical to the past tense for regular verbs, but often different for irregular verbs.
• -ing form (going, writing, climbing) — serves as the present participle and gerund.

The verb be is a special case with more forms than any other English verb (am, is, are, was, were, been, being). Modal verbs like can, must, and should have fewer forms than typical verbs.

Main Verbs and Auxiliaries

Verbs in English often appear in combinations: one or more auxiliary verbs paired with a main verb.

• The dog was barking very loudly.
• My hat has been cleaned.
• Jane does not really like us.

The first verb in the combination is the finite verb (it carries tense and agrees with the subject). The rest are nonfinite (infinitives or participles). Notice that these verbs don't always sit next to each other — as in does not really like.

Tense, Aspect, and Mood

English expresses tense (time reference), aspect (how an action unfolds over time), and mood (the speaker's attitude toward the action) mostly through verb combinations rather than word endings. That's why you'll encounter labels like "present progressive" or "conditional perfect" — these are specific tense–aspect–mood combinations built with auxiliaries.

Self-check: If you can change the time of a sentence by swapping one word (She runs → She ran), that word is the verb.

Keep Practising

To build your verb skills from the ground up, try these challenges: Basics. "To be" in Present Tense, Basics. Common Uses of Auxiliary Verbs, and Transitive and Intransitive Verbs.

Idiom

An idiom is a common word or phrase with a culturally understood meaning that differs from what its composite words' denotations would suggest; i.e. the words together have a meaning that is different from the dictionary definitions of the individual words.

By another definition, an idiom is a speech form or an expression of a given language that is peculiar to itself grammatically or cannot be understood from the individual meanings of its elements.

For example, an English speaker would understand the phrase "kick the bucket" to mean "to die" – and also to actually kick a bucket. Furthermore, they would understand when each meaning is being used in context.

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.

C1 | Advanced

C1 is the fifth of six levels in the Common European Framework of Reference for Languages (CEFR), sitting between B2 (Upper-Intermediate) and C2 (Proficiency). It's classified as Advanced — the stage where you stop translating in your head and start thinking in English.

What a C1 user can do

At this level, you're expected to handle complex, demanding language across a wide range of situations:

• Reading — You can understand long, complex texts, including specialized articles and technical instructions outside your own field. You pick up on implicit meaning, not just what's stated directly.
• Speaking — You express yourself fluently and spontaneously with minimal searching for words. You use language flexibly for social, academic, and professional purposes.
• Writing — You produce clear, well-structured, detailed text on complex subjects, with controlled use of organizational patterns, connectors, and cohesive devices.
• Listening — You follow extended speech even when it isn't clearly structured or when relationships between ideas are only implied.

What C1 grammar looks like

C1-level grammar goes well beyond accuracy with tenses and articles. You're expected to use advanced structures naturally, including:

• Inversion for emphasis (Rarely have I seen such dedication.)
• Mixed and advanced conditionals (Had she known, she would never have agreed.)
• Subjunctive forms in formal contexts (It's essential that he be informed.)
• Cleft sentences for focus (What concerns me is the timeline.)
• Complex noun phrases and nominalization (The government's repeated failure to act…)

The difference between B2 and C1 isn't just knowing these structures exist — it's using them appropriately and with control across different registers.

Self-check: If you can read an opinion piece in The Guardian or The Economist and follow the argument without a dictionary, and if you can write a structured response disagreeing with it, you're likely operating at C1.

How C1 fits in the CEFR scale

The CEFR has six levels: A1 → A2 → B1 → B2 → C1 → C2. C1 is where most universities and professional bodies set their language requirements for non-native speakers.

Ready to test yourself? Try Pass the Test to Determine Your English CEFR Level or go straight to the C1/C2-level test. You can also practice key C1 structures like Inversion and Conditional Subjunctive.

Difficulty: Hard

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