Adjective Clause

An adjective clause—also called an adjectival or relative clause—will meet three requirements:

• First, it will contain a subject and verb.
• Next, it will begin with a relative pronoun [who, whom, whose, that, or which] or a relative adverb [when, where, or why].
• Finally, it will function as an adjective, answering the questions What kind? How many? or Which one?

The adjective clause will follow one of these two patterns:

Relative Pronoun or Adverb + Subject + Verb

Relative Pronoun as Subject + Verb

Here are some examples:

Whose big, brown eyes pleaded for another cookie

Whose = relative pronoun; eyes = subject; pleaded = verb.

Why Fred cannot stand sitting across from his sister Melanie

Why = relative adverb; Fred = subject; can stand = verb [not, an adverb, is not officially part of the verb].

That bounced across the kitchen floor

That = relative pronoun functioning as subject; bounced = verb.

Who hiccupped for seven hours afterward

Who = relative pronoun functioning as subject; hiccupped = verb.

Avoid writing a sentence fragment.

An adjective clause does not express a complete thought, so it cannot stand alone as a sentence. To avoid writing a fragment, you must connect each adjective clause to a main clause.

Read the examples below. Notice that the adjective clause follows the word that it describes.

Diane felt manipulated by her beagle Santana, whose big, brown eyes pleaded for another cookie.

Chewing with her mouth open is one reason why Fred cannot stand sitting across from his sister Melanie.

Snarling and skidding on the smooth tile, Oreo and Skeeter, Madison's two dogs, competed for the hardboiled egg that bounced across the kitchen floor.

Laughter erupted from Annamarie, who hiccupped for seven hours afterward.

Punctuate an adjective clause correctly.

Punctuating adjective clauses can be tricky. For each sentence, you will have to decide if the adjective clause is essential or nonessential and then use commas accordingly.

Essential clauses do not require commas. An adjective clause is essential when you need the information it provides.

Look at this example:

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

Vegetables is nonspecific. To know which ones we are talking about, we must have the information in the adjective clause. Thus, the adjective clause is essential and requires no commas.

If, however, we eliminate vegetables and choose a more specific noun instead, the adjective clause becomes nonessential and does require commas to separate it from the rest of the sentence.

Read this revision:

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

sumber :

http://www.chompchomp.com/terms/adjectiveclause.htm

http://www.english-grammar-revolution.com/adjective-clauses.html