Here are some terms that you should know.

ANTECEDENT The noun that a pronoun stands for

CLAUSE A structure with a subject and a predicate

EXPLETIVE A word that enables a writer or speaker to shift the stress in a sentence or to embed one sentence in another: "A fly is in my soup/ There's a fly in my soup."

GENDER A feature of personal pronouns and certain nouns that distinguishes masculine (he), feminine (she), and neuter (it)

NUMBER A feature of nouns and pronouns, referring to singular and plural

PERSON A feature of personal pronouns that distinguishes the speaker or writer (first person), the person or thing spoken to (second person), and the person or thing spoken of (third person)

1. Every pronoun must have a conspicuous antecedent.
2. Every pronoun must agree with its antecedent in number, gender, and person.

Pronoun reference problems occur in the following instances.

1. When a pronoun refers to either of two antecedents
   

   
   Incorrect: Doris told Shirley that she was getting fat. (Which one is getting fat?)
   
   Correct: Doris told Shirley, "I'm getting fat."

2. When a pronoun refers to an unspecified antecedent

   
   Incorrect: A strange car followed us closely, and he kept blinking his lights at us. (Who or what kept blinking the light at us?)
   
   Correct: A strange car followed us closely, and its driver kept blinking his lights at us.

3. When this, that, and which refer to the general idea of a preceding clause or sentence rather than the preceding word

   
   Incorrect: The students could not understand the pronoun reference handout, which annoyed them very much. (What annoyed the students? Was it the handout or not being able to understand the handout?)
   
   Correct: The students could not understand the pronoun reference handout, a fact which annoyed them very much. (The students were annoyed because they could not understand the pronoun reference handout.)

4. When a pronoun refers to an unexpressed but implied noun

   
   Incorrect: My husband wants me to become a dancer at Sammy's Go-Go, but I'm not interested in it. (What is not interesting?)
   
   Correct: My husband wants me to become a dancer at Sammy's Go-Go, but I'm not interested in being that kind of dancer.

5. When it is used as something other than an expletive to postpone a subject

   
   Incorrect: It says in today's paper that the newest shipment of cars from Detroit, Michigan, seems to include outright imitations of European models.
   
   Correct: Today's newspaper says that the newest shipment of cars from Detroit, Michigan, seems to include outright imitations of European models.
   
   Incorrect: The football game was cancelled because it was bad weather. (What was bad weather?)
   
   Correct: The football game was cancelled because the weather was bad.
   

6. When they or it is used to refer to something or someone indefinitely, and there is no definite antecedent

   
   Incorrect: At the job placement office, they told me to stop wearing ripped jeans to my interviews. (Who told me?)
   
   Correct:
   At the job placement office, my counselor told me to stop wearing ripped jeans to my interviews.
   
   At the job placement office, I was told to stop wearing ripped jeans to my interviews.

7. When the pronoun does not agree with its antecedent in number, gender, or person

   
   Incorrect:: Any graduate student, if they are interested, may attend the lecture. (student--singular; they--plural)
   
   Correct:
   Any graduate student, if he is interested, may attend the lecture.
   
   Any graduate student, if he or she is interested, may attend the lecture.
   
   Incorrect: Many Americans are concerned that the overuse of slang and colloquialisms is corrupting its language. (Americans--plural; its--singular)
   
   Correct: Many Americans are concerned that the overuse of slang and colloquialisms is corrupting their language.
   
   Incorrect:: The Board of Regents will not make a decision about tuition increase until their March meeting. (Board of Regents--singular;their--plural)
   
   Correct: The Board of Regents will not make a decision about tuition increase until its March meeting.

8. When a noun or pronoun has no expressed antecedent

   
   Incorrect: In the President's address to the union, he promised no more taxes. (Who is he?)
   
   Correct: In his address to the union, the President promised no more taxes.