Gerund

The gerund takes the same form (ending in -ing) as the present participle, but is used as a noun (or rather the verb phrase introduced by the gerund is used as a noun phrase). Many uses of gerunds are thus similar to noun uses of the infinitive. Uses of gerunds and gerund phrases are illustrated below:

As subject or predicative expression:

• Solving problems is satisfying.
• My favorite activity is spotting butterflies.

As object of certain verbs that admit such constructions:

• I like solving problems.
• We tried restarting the computer.

In a passive-type construction after certain verbs, with a gap (zero) in object or complement position, understood to be filled by the subject of the main clause:

• That floor wants/needs scrubbing.
• It doesn't bear thinking about.

As complement of certain prepositions:

• No one is better at solving problems.
• Before jogging, she stretches.
• After investigating the facts, we made a decision.
• That prevents you from eating too much.

It is considered grammatically correct to express the agent(logical subject) of a gerund using a possessive form (they object to my helping them), although in informal English a simple noun or pronoun is often used instead (they object to me helping them).

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.

Preposition

Prepositions form a closed word class, although there are also certain phrases that serve as prepositions, such as in front of.

A single preposition may have a variety of meanings, often including temporal, spatial and abstract. Many words that are prepositions can also serve as adverbs. Examples of common English prepositions (including phrasal instances) are of, in, on, over, under, to, from, with, in front of, behind, opposite, by, before, after, during, through, in spite of or despite, between, among, etc.

A preposition is usually used with a noun phrase as its complement.

A preposition together with its complement is called a prepositional phrase.

Examples are in England, under the table, after six pleasant weeks, between the land and the sea.

A prepositional phrase can be used as a complement or post-modifier of a noun in a noun phrase, as in the man in the car, the start of the fight; as a complement of a verb or adjective, as in deal with the problem, proud of oneself; or generally as an adverb phrase.

English allows the use of "stranded" prepositions. This can occur in interrogative and relative clauses, where the interrogative or relative pronoun that is the preposition's complement is moved to the start (fronted), leaving the preposition in place. This kind of structure is avoided in some kinds of formal English.

For example:

• What are you talking about? (Possible alternative version: About what are you talking?)
• The song that you were listening to ... (more formal: The song to which you were listening ...)

Notice that in the second example the relative pronoun that could be omitted.

Stranded prepositions can also arise in passive voice constructions and other uses of passive past participial phrases, where the complement in a prepositional phrase can become zero in the same way that a verb's direct object would: it was looked at; I will be operated on; get your teeth seen to.

The same can happen in certain uses of infinitive phrases: he is nice to talk to; this is the page to make copies of.

B1 / Intermediate

A CEFR B1 level English language user is considered to be at an intermediate level. A B1 level English language user is expected to have the following abilities:

• Can understand sentences and frequently used expressions related to areas of most immediate relevance (e.g. very basic personal and family information, shopping, local geography, employment).
• Can communicate in simple and routine tasks requiring a simple and direct exchange of information on familiar and routine matters.
• Can describe in simple terms aspects of their background, immediate environment and matters in areas of immediate need.
• Can understand the main points of clear standard input on familiar matters regularly encountered in work, school, leisure, etc.
• Can produce simple connected text on topics that are familiar or of personal interest.
• Can describe experiences and events, dreams, hopes & ambitions and briefly give reasons and explanations for opinions and plans.

At B1 level, English language users are expected to have a basic level of proficiency in the language. They should be able to understand and produce language in simple and routine tasks, and be able to communicate in familiar and routine matters. They should be able to understand the main points of clear standard input on familiar matters and be able to produce simple connected text on topics that are familiar or of personal interest. They are able to express themselves with a degree of fluency, but with some hesitation, and occasional errors in grammar and vocabulary.

B1 | Intermediate.

Difficulty: Medium

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