Imperative sentences give commands. This type of sentence is
special because it can have an implied subject. This means that
the subject doesn’t actually have to be part of the sentence; it can be implied,
or stated indirectly. However, the only implied subject that an imperative
sentence can have is “you”.
Imperative sentences don’t always have to have an implied
subject, though. When an imperative sentence doesn’t have an implied subject,
the subject can be anything that makes sense, just like any other type of
sentence.
Imperative sentences end with a period or an exclamation
point, depending on the strength of the command. Consider the following
examples:
Come here.
Joey, clean your room.
Somebody call 911!
The first example is a simple command with the implied
subject of "you". Notice that the subject is not actually a word in
the sentence, but the reader can tell that the writer is really saying “You
come here.” The writer doesn’t want this sentence to carry much emotion, so the
sentence ends with a period.
The second example is another imperative sentence with a
regular subject, “Joey”. The writer doesn’t want this sentence to have much
emotion, so it ends with a period.
The third example is an imperative sentence with a regular
subject, “Somebody”. This sentence ends with an exclamation point because the
writer wants to add more emotion to it.