An infinitive is a verbal consisting of to + a verb, and it acts like a subject, direct object, subject complement, adjective or adverb in a sentence.
Gerunds are verbals that function as nouns and have an –ing ending.
An auxiliary verb (or a helping verb) is a verb that adds meaning in the sentence, such as to express tense, aspect,modality, voice, emphasis, etc. An auxiliary verb is most generally understood as a verb that “helps” another verb by adding grammatical information to it.
Certain auxiliaries have contracted forms, such as had/ would and will/ shall.
Linking verbs connect the subject of a sentence with an adjective, noun, or descriptive phrase. To find a linking verb, remember that they do not indicate action in a sentence. They describe a state of being, a result, or one of the five senses and do not have an object.
In grammar, the object is whatever is receiving the action of the subject. Since linking verbs do not suggest action, there is no receiver. Instead, what follows a linking verb is known as the subject complement.
Subject Complement
The subject complement is the descriptive word or phrase that the linking verb connects to the subject of the sentence. It can be a noun, adjective, or phrase. Generally, the structure of a sentence with a linking verb will be:
(Subject) + Linking Verb + Subject Complement
Remember that linking verbs are not action words. Compare the usage of “appeared” in both the sentences below:
Sentence A: Daisy appeared onstage in a princess costume.
Sentence B: Daisy appeared troubled by her brother's phone call.
In both A and B, “Daisy” is our subject.
Look at how “appeared” is being used in sentence A. It’s describing an action that Daisy has accomplished. “Onstage” is where Daisy appeared, and the prepositional phrase afterwards adds some more detail of the scene.
However, “appeared” in sentence B is describing Daisy’s current state of being, how she is perceived by others. The subject complement, “troubled” describes more about how Daisy appears.
A simple way to identify a linking verb is to replace the verb in question with “seems.” If the idea makes sense, then the verb is a linking verb; if not, then the verb is something else. Let’s try this technique with the above sentences:
Sentence A: Daisy seems onstage in a princess costume.
Sentence B: Daisy seems troubled by her brother's phone call.
In sentence A makes sense grammatically when we use “seems,” this verb is not a linking verb because “onstage” is not modifying Daisy’s identity. Instead “onstage” is a location and Daisy took action, or “appeared”, to get there, which is the proper idea of sentence A.
With sentence B, the original idea of the sentence is kept intact. “Seems” links Daisy’s state of being to “troubled.”.
Modal verbs are used to express possibility, obligation, advice, permission, ability, …
Will
Shall
Would
Should
Ought to
Must
Mustn’t
May
Might
Can
Could
Have to/ Has to
Don’t/ Doesn’t have to