Editing Dependent clause (section)

====English punctuation====
The punctuation of an adjective clause depends on whether it is essential (restrictive) or nonessential (nonrestrictive) and uses commas accordingly. Essential clauses are not set off with  commas; nonessential clauses are. An adjective clause is essential if the information it contains is necessary to the meaning of the sentence:

*The vegetables ''that people often leave uneaten'' are usually the most nutritious.

The word "vegetables" is non-specific. Accordingly, for the reader to know which are being mentioned, one must have the information provided in the adjective clause (in italics). Because it restricts the meaning of "vegetable", the adjective clause is called a restrictive clause. It is essential to the meaning of the main clause and uses no commas (and so does not experience a pause when spoken).

However, if the additional information does not help to identify more narrowly the identity of the noun antecedent but rather simply provides further information about it, the adjective clause is nonrestrictive and so requires commas (or a spoken pause) to separate it from the rest of the sentence:

*Broccoli, ''which people often leave uneaten'', is very nutritious.

Depending on context, a particular noun could be modified by either a restrictive or nonrestrictive adjective clause. For example, while "broccoli" is modified nonrestrictively in the preceding sentence, it is modified restrictively in the following.

*The broccoli ''which (''or'' that) people leave uneaten'' is often nutritious.