To minimize errors with adjective clauses, remember that the relative pronoun (who, whom, whose, that, which) has two roles: it connects the dependent clause to the independent clause, and it is part of the dependent clause (usually its subject or object).
The hand that rocks the cradle rules the world. [That refers to hand and is also the subject of the dependent clause that rocks the cradle.]
The man whom I met was going to St. Ives. [Whom refers to man and is also the object of the dependent clause whom I met.]
Do not add a second pronoun to an adjective clause. We received the sweater that you sent it yesterday.
A stone that it rolls gathers no moss.
Do not use an adjective clause as a subject or object.
A noun clause should begin with a relative pronoun or a subordinating conjunction (such as that, if, or whether), not a preposition.
I regret telling my supervisor about (that) my co-worker was lazy
In a sentence with an adverb clause, do not use a coordinating conjunction (such as and, but, or or) in addition to a subordinating conjunction.
Although I spoke the truth, but I was tactless to do so.
dependent clauses
A dependent (or subordinate) clause is a word group with a subject and a predicate that cannot stand alone as a sentence. The dependent clause begins with a subordinating conjunction (although, because, or since, for example) or a relative pronoun (such as who, which, or that), and it needs an independent clause to complete its meaning. In a sentence, a dependent clause may serve as a noun, an adjective, or an adverb. (See also subordination.)
NOUN CLAUSES
A noun clause can be a subject, an object, or a complement.
That we had all passed pleased us, [subject]
I learned that drugs ordered by brand name can cost several times as much as drugs ordered by genetic name, [direct object of verb]
The trouble is that not all pharmacies carry generic drugs, [subject complement]
Generic drugs should be available to whoever wants them, [object of preposition use whoever rather than whomever because the word is the subject of the depen dent clause]
He got there first by asking which way was shorter, [object of a verbal]
Give whoever wants one a copy [indirect object of verb]
She left home and made herself what she wanted to be. [object complement]
ADJECTIVE CLAUSES
An adjective clause functions as an adjective by modifying a noun or pronoun in another clause.
The student whom we met yesterday showed us her collection of albums, which includes all of Paul McCartney's work, [modifying the nouns student and albums]
The man who called earlier is here, [modifying man]
The fourth quarter is the period when defense will be critical, [modifying period]
Adjective clauses may be restrictive or nonrestrictive. If the clause is essential to limiting the meaning of the noun, it is restrictive and not set off by commas. (See also restrictive and nonrestrictive elements.)
The quotations that adorn the book jacket were compiled from a series of favorable reviews.
If the clause is not intended to limit the meaning of the noun but merely provides further information about it, the clause is nonrestrictive and set off by commas.
Other quotations, which we chose not to include, expressed more negative opinions.
If adjective clauses are not placed carefully, they may appear to modify the wrong noun or pronoun.
ADVERB CLAUSE
Adverb clauses may express relationships of time, cause, result, or degree. They usually modify verbs but may also modify adjectives, adverbs, or whole clauses.
You are making an investment when you buy a house, [time]
A title search was necessary because the bank would not issue a loan without one. [cause]
The cost of financing a home will be higher if discount points are charged, [result]
Monthly mortgage payments should not be much more than a person earns in one week, [degree]
