In English, sentences need explicit subjects, but this is not so in conversational Korean.

A few of them depicted explicit homoerotic subjects.

Clauses with the verb haber do not have an explicit subject.

But abortion is never the explicit subject of these confirmation battles.

Sometimes, though an explicit subject is not necessary to form a grammatically correct sentence, one may be stated in order to emphasize its importance.

Some sentences, however, do not allow a subject at all and in some other cases an explicit subject would sound awkward or unnatural:

Too often, art that lacks an explicit subject is thought to be without content and dismissed (this happens especially to abstract art).

In a nominative absolute construction, where the participle is given an explicit subject (which will normally be different than that of the main clause):

English and French, on the other hand, require an explicit subject in this sentence.

Some sentences do not allow a subject in any form while, in other cases an explicit subject without particular emphasis, would sound awkward or unnatural.