When they … on holiday, a neighbour … their cat. (go, feed)

2. He … early when he … study a lot. (get up, have to)

3. If I … late, I usually … to the college. (not be, walk)

4. What … if you … problems getting to sleep? (you, / do, have)

5. If James … to see her, she … the door. (come, not answer)

6. If I … balcony or a garden, I … it there, but this is the best place for it.(have, put)

7. If you …a wallet in the street, what … you do? (find, do)

8. If I … you, I … the truth. (be, tell)

9. If he … younger, he … the job. (be, get)

10. If we … more, we … better. (train, play)

11. I wish I … with you, but I have to stay at home. (can come)

12. I wish I … a car. (have)

1. When they go on holiday, a neighbor feeds their cat.
To understand this sentence, we need to determine the verb forms that match the subject pronouns "they" and "a neighbor." In this case, "they" refers to a group of people who are going on holiday, so the verb form used is "go." The neighbor is the one who performs the action of feeding the cat, so the verb form used is "feeds."

2. He gets up early when he has to study a lot.
In this sentence, the subject pronoun "he" is performing the action of getting up early. The reason for getting up early is given by the dependent clause "when he has to study a lot." The verb forms used are "gets up" and "has to."

3. If I am late, I usually walk to the college.
This sentence is a conditional sentence, expressing a hypothetical situation. The subject pronoun "I" is the subject of the sentence. The conditional clause "if I am late" introduces the condition under which the action in the main clause occurs. The verbs used are "am" and "walk."

4. What do you do if you have problems getting to sleep?
This sentence also presents a conditional situation. The interrogative pronoun "what" is used at the beginning to ask about the action taken when having problems getting to sleep. The subject pronoun "you" is the subject of the sentence. The interrogative verb form "do" is used, as well as the verb form "have."

5. If James comes to see her, she does not answer the door.
Again, this sentence introduces a hypothetical situation. The subject pronoun "James" is the subject of the conditional clause, and the subject pronoun "she" is the subject of the main clause. In this case, the verb forms used are "comes" and "does not answer."

6. If I have a balcony or a garden, I put it there, but this is the best place for it.
This sentence also presents a hypothetical situation. The subject pronoun "I" is the subject of both clauses. The verb forms used are "have" and "put."

7. If you find a wallet in the street, what do you do?
This sentence asks about the action to be taken when finding a wallet in the street. The subject pronoun "you" is the subject of the sentence, and the verb forms used are "find" and "do."

8. If I were you, I would tell the truth.
Again, we have a conditional situation. The subject pronoun "I" is the subject of the conditional clause, and the subject pronoun "I" is also the subject of the main clause. In this case, the verb forms used are "were" and "would tell."

9. If he were younger, he would get the job.
This sentence is another example of a conditional sentence. The subject pronoun "he" is the subject of both clauses. The verb forms used are "were" and "would get."

10. If we train more, we will play better.
This sentence expresses a conditional situation. The subject pronoun "we" is the subject of both clauses. The verb forms used are "train" and "will play."

11. I wish I could come with you, but I have to stay at home.
This sentence expresses a desire or longing for a different situation. The subject pronoun "I" is the subject of both clauses. The verb forms used are "could come" and "have to stay."

12. I wish I had a car.
This sentence also expresses a desire for a different situation. The subject pronoun "I" is the subject of the sentence. The verb form used is "had."