Note: The subject must always agree with the verb in number and person. The subject ‘ the twins’ does not act here but simply expresses the verb ‘ to be’ (in this occurrence: being here) and the relation to the location (place).In such a case, it often appears with the verb ‘ to be’ or similar ones accordingly: At times, we cannot really say that the subject is acting, that is, performing an action.Interrogative clauses also have a subject, represented by ‘ they’ here.“ Have they invited you to the wedding?”.This negated sentence contains the abstract noun ‘ friendship’, which can also be subject.“ Friendship doesn’t need daily conversation.”.In this positive statement, the person Andrew becomes the subject and performs the activity represented by the verb ‘ to cook’.Subjects are typically persons, animals, or things (concrete or abstract).All types of sentences must contain one – except for imperatives. In English grammar, it is one of the most critical parts of a sentence (which means it is a constituent) and cannot be left out without making it ungrammatical.

Thus, it shows who or what is doing something. Basically, the subject carries out the action that the verb in the sentence indicates or expresses.

What is the subject of a sentence