Rewrite the sentence by correcting the error in pronoun reference or agreement. and state whether the error is in the pronoun reference (ref) or pronoun agreement (agr)

1. after jeff talked to his brother about the project, he went home.

2. every frugal shopper counts their coupons before they shop.

3. someone decided to leave their mess behind for others to clean up.

4. the crowd sat through two hours of rainy soccer. it ended in a tie.

5. neither the smiths nor mr. paulson remembered to purchase their hunting license.

1. After Jeff talked to his brother about the project, he went home. (REF)

In this example, the pronoun “he” has not a clear antecedent as it may refer to “Jeff” or “his brother”. In order to improve this sentence, it can be rewrite in this way:

a)  After Jeff talked to his brother about the project, the former/ the latter went home.

2. Every frugal shopper counts their coupons before they shop.(AGR)

In this sentences, the pronoun “their” does not agree with its antecedent that is a singular noun (Every frugal shopper). The corrected sentences are:

a)Every frugal shopper counts his or her coupons before they shop.

b)Every frugal shopper counts the coupons before they shop.

c)Every frugal shopper counts everyone´s coupons before they shop

3. Someone decided to leave their mess behind for others to clean up. (AGR)

As in the previous sentence, the pronoun “their” does not agree with its antecedent (someone). The corrected sentences are:

a)Someone decided to leave his or her mess behind for others to clean up.

b)A mess was left behind for others to clean up.

4. The crowd sat through two hours of rainy soccer. It ended in a tie. (REF)

The pronoun “it” has not a clear antecedent as it is not stated in the previous sentence. The reader can infer that “it” refers to “soccer match”.

a)The crowd sat through two hours of rainy soccer. The soccer match ended in a tie.

5. Neither the Smiths nor Mr. Paulson remembered to purchase their hunting license. (AGR)

The pronoun “their” does not match its antecedent.  

a)Neither the Smiths nor Mr. Paulson remembered to purchase his hunting license.

The sentences that have a pronoun reference error are the following ones: 1 and 4. The sentences that have a pronoun agreement error are the following ones: 2, 3 and 5.

Explanation:

The first sentence has a pronoun reference error because it is not clear whether the personal pronoun "he" refers back to Jeff or to the NP "his brother".  You could fix this by using the structure the former/the latter (see a).   Likewise,  sentence 4 also has a pronoun reference error. It is not clear to which NP the pronoun "it" refers. It can't refer back to the NP "the crowd", so it should refer to "rainy soccer".  You could fix this by changing this pronoun for the NP "the game" (see b).

Then, sentence 2, 3 and 5 have pronoun agreement error because they all make use of singular they.  Singular they is the use of the pronoun "they" or any of derivative forms (them, their, theirs, themselves) as a gender-neutral singular pronoun. This use particularly occurs with an unspecified antecedent. In order to fix this error, you could use the specific personal pronouns his/her (see c, d, and e). What is more, in sentence 5 you should take into account that the pronoun refers to both the Smiths and Mr. Paulson. So you should use the singular personal pronoun "his" since Mr. Paulson is the closest NP to the pronoun.

a) After Jeff talked to his brother about the project, the former/the latter went home.

b) The crowd sat through two hours of rainy soccer. The game ended in a tie.

c) Every frugal shopper counts his/her coupons before they shop. Also,  every frugal shopper counts the coupons before they shop.

d) Someone decided to leave his/her mess behind for others to clean up. Also, someone decided to leave a mess behind for others to clean up.

e) Neither the Smiths nor Mr. Paulson remembered to purchase his hunting license. Also, neither the Smiths nor Mr. Paulson remembered to purchase the hunting license.