a or b) for each number as well as an explanation of why you made that choice. just need help explaining why?

Answer A
4a. John has become a rather good actor.
4b John has became a rather good actor.
Answer A
5a. Some athletes have taken drug tests to prove they are not on steroids.
5b. Some athletes have took drug tests to prove they are not on steroids.
Answer B
6a. I lay my book on the table, but now I cannot find it.
6b. I laid my book on the table, but now I cannot find it.
Answer A
7a. I was interested in working on the presidential campaign if the opportunity still exists.
7b. I am interested in working on the presidential campaign if the opportunity still exists.
Verb form and verb tense Answer B
8a. Since American Idol premiered on television, many talented contestants have appeared on the show.
8b. Since American Idol premiered on television, many talented contestants appeared on the show.
Verb form and verb tense Answer a
9a. The ancient Egyptians built pyramids as burial sites for their leaders.
9b. The ancient Egyptians have built pyramids as burial sites for their leaders.
Identifying antecedents Answer A
10a. The antecedent in the following sentence is students: Students in online classes have to be organized to keep up with their assignments.
10b. The antecedent in the following sentence is class: Students in online classes have to be organized to keep up with their assignments.
Identifying antecedents Answer A
11a. The antecedent in the following sentence is Doctors: Doctors should
schedule more time for patients so they do not spend so much time in the waiting room.
11b. The antecedent in the following sentence is patients: Doctors should schedule more time for patients so they do not spend so much time in the waiting room.
Pronoun-antecedent agreement answer B 12a. When a driver wants to buy a new vehicle, he or she usually test drives them.
12b. When a driver wants to buy a new vehicle, he or she usually test drives it.
Pronoun-antecedent agreement Answer B 13a. Most presenters spoke without looking at his or her notes.
13b. Most presenters spoke without looking at their notes.
Pronoun-antecedent agreement Answer B 14a. You may rent a movie or a video game for just one night if they are new.
14b. You may rent a movie or a video game for just one night if it is new.
Pronoun-antecedent agreement with indefinite pronouns Answer B
15a. Neither the mayor nor the council members have filed their reports.
15b. Neither the mayor nor the council members have filed his or her reports.
Pronoun-antecedent agreement with indefinite pronouns answer A
16a. Anyone who requests a copy of the game may have it for their video library.
16b. Anyone who requests a copy of the game may have it for his or her video library.
Pronoun-antecedent agreement with indefinite pronouns answer A
17a. Each of the applicants must submit his or her completed form to the interviewer.
17b. Each of the applicants must submit their completed forms to the interviewer.
Pronoun case answer A
18a. My brother knows more about technology than me.
18b. My brother knows more about technology than I.
Pronoun case answer B
19a. Please send an invitation to Bob and she.
19b. Please send an invitation to Bob and her.
Pronoun case answer A
20a. My best friend and I are going to Hawaii this summer.
20b. My best friend and me are going to Hawaii this summer.
Pronoun case for who and whom Answer A 21a. Who was the star of last year’s award-winning movie?
21b. Whom was the star of last year’s award-winning movie?
Pronoun case for who and whom answer A 22a. To who should we send the letter of commendation?
22b. To whom should we send the letter of commendation?
Pronoun case for who and whom answer B
23a. Jon Bon Jovi, who is a well-known singer and actor, once owned an arena
football team.
23b. Jon Bon Jovi, whom is a well-known singer and actor, once owned an arena football team.
Vague pronouns Answer B
24a. When the car hit a tree, it made a terrible noise.
24b. The car made a terrible noise as it crashed into a tree.
Vague pronouns answer A
25a. Air pollution normally increases along with population growth. This increasing pollution is a big problem for many cities.
25b. Air pollution normally increases along with population growth. This is a big problem for many cities.
Can any one help me with a explaition why these are the answer.

They are not all correct.

Why did you choose these answers? For instance, the past participle of "become" is "become."

http://grammar.ccc.commnet.edu/grammar/index2.htm

Use this index to look up the explanations you need. Look up these things:

verb tenses and uses
different pronoun and antecedent topics

Sure! I'll provide explanations for each of the answers:

4a. John has become a rather good actor.
Explanation: In this sentence, "become" is the correct verb form to use because it's describing an ongoing action that has happened in the past and is still true in the present. The word "has" indicates the present perfect tense, and "become" is the correct past participle form of the verb.

5b. Some athletes have took drug tests to prove they are not on steroids.
Explanation: The correct verb form is "taken" instead of "took." "Have taken" is the correct present perfect tense to indicate that the action has happened in the past and is still relevant in the present.

6b. I laid my book on the table, but now I cannot find it.
Explanation: "Laid" is the correct past tense form of the verb "lay" to indicate an action that happened in the past.

7a. I was interested in working on the presidential campaign if the opportunity still exists.
Explanation: "Was interested" is the correct past tense form to indicate a past state of being interested in the presidential campaign.

8a. Since American Idol premiered on television, many talented contestants have appeared on the show.
Explanation: "Have appeared" is the correct present perfect tense to indicate an action that started in the past and is still true in the present.

9a. The ancient Egyptians built pyramids as burial sites for their leaders.
Explanation: "Built" is the correct past tense form of the verb "build" to indicate an action that happened in the past.

10a. The antecedent in the following sentence is students: Students in online classes have to be organized to keep up with their assignments.
Explanation: The word "students" is the antecedent because it's the noun that the pronoun "they" refers to in the sentence.

11b. The antecedent in the following sentence is patients: Doctors should schedule more time for patients so they do not spend so much time in the waiting room.
Explanation: The word "patients" is the antecedent because it's the noun that the pronoun "they" refers to in the sentence.

12b. When a driver wants to buy a new vehicle, he or she usually test drives it.
Explanation: The pronoun "it" is used to refer to the noun "vehicle" in the sentence.

13b. Most presenters spoke without looking at their notes.
Explanation: The pronoun "their" is used to refer to the noun "presenters" in the sentence.

14b. You may rent a movie or a video game for just one night if it is new.
Explanation: The pronoun "it" is used to refer to the noun "movie or video game" in the sentence.

15a. Neither the mayor nor the council members have filed their reports.
Explanation: The pronoun "their" is used to refer to the plural nouns "mayor" and "council members" in the sentence.

16b. Anyone who requests a copy of the game may have it for his or her video library.
Explanation: The pronoun "his or her" is used to refer to the noun "anyone" in the sentence.

17a. Each of the applicants must submit his or her completed form to the interviewer.
Explanation: The pronoun "his or her" is used to refer to the noun "each applicant" in the sentence.

18b. My brother knows more about technology than I.
Explanation: The pronoun "I" is the correct pronoun because it follows the verb "than" and acts as the subject of the sentence.

19b. Please send an invitation to Bob and her.
Explanation: The pronoun "her" is correct because it functions as an object in the sentence.

20a. My best friend and I are going to Hawaii this summer.
Explanation: The pronoun "I" is the correct pronoun to use because it is the subject of the sentence.

21a. Who was the star of last year’s award-winning movie?
Explanation: "Who" is the correct pronoun to use as it is the subject of the sentence.

22b. To whom should we send the letter of commendation?
Explanation: "Whom" is the correct pronoun to use because it functions as the object of the preposition "to."

23a. Jon Bon Jovi, who is a well-known singer and actor, once owned an arena football team.
Explanation: "Who" is the correct pronoun to use because it refers to Jon Bon Jovi, who is the subject of the sentence.

24a. When the car hit a tree, it made a terrible noise.
Explanation: "It" is a vague pronoun in this sentence because it's unclear what "it" is referring to. To make the sentence clearer, it's better to replace "it" with "the car" to specify what is making the noise.

25b. Air pollution normally increases along with population growth. This is a big problem for many cities.
Explanation: The pronoun "This" refers to the preceding sentence and helps to connect the two sentences, making the overall meaning clearer.