1. Cathy isn’t at work now. She home. 2. I to New York once before and I really liked it. 3. Jim’s grandparents aren’t in the garden at the moment. They into the kitchen. 4. Harry to Brighton four times. He really enjoyed that. 5. Martin and Ann to the cinema. They left two hours ago. 6. Bob isn't here now. He to the gym. 7. Amanda and her sister aren’t here. They home some time ago. 8. Peter didn't know that Emma was visiting Warsaw today. He home. 9. I to London. I'll be back next month. 10. He to restaurant. He'll be back at 10 o clock

1. Cathy isn’t at work now. She is at home.
Explanation: The word "isn't" is a contraction of "is not" which indicates the present tense. Since Cathy is not currently at work, we can say that she "is at home."

2. I to New York once before and I really liked it.
Correction: I went to New York once before and I really liked it.
Explanation: The word "to" is not correct in this context. Instead, we should use the past tense form of the verb "go," which is "went." Therefore, the correct sentence should be "I went to New York once before and I really liked it."

3. Jim’s grandparents aren’t in the garden at the moment. They are in the kitchen.
Explanation: The word "aren't" is a contraction of "are not" which indicates the present tense. Since Jim's grandparents are not currently in the garden, we can say that they "are in the kitchen."

4. Harry to Brighton four times. He really enjoyed that.
Correction: Harry has been to Brighton four times. He really enjoyed that.
Explanation: The verb "to be" is not correct in this context. Instead, we should use the present perfect tense of the verb "go," which is "has been." Therefore, the correct sentence should be "Harry has been to Brighton four times. He really enjoyed that."

5. Martin and Ann to the cinema. They left two hours ago.
Correction: Martin and Ann went to the cinema. They left two hours ago.
Explanation: The verb "to" is not correct in this context. Instead, we should use the past tense form of the verb "go," which is "went." Therefore, the correct sentence should be "Martin and Ann went to the cinema. They left two hours ago."

6. Bob isn't here now. He is at the gym.
Explanation: The word "isn't" is a contraction of "is not" which indicates the present tense. Since Bob is not currently here, we can say that he "is at the gym."

7. Amanda and her sister aren’t here. They went home some time ago.
Explanation: The word "aren't" is a contraction of "are not" which indicates the present tense. Since Amanda and her sister are not currently here, we can say that they "went home some time ago."

8. Peter didn't know that Emma was visiting Warsaw today. He is at home.
Correction: Peter didn't know that Emma was visiting Warsaw today. He stayed at home.
Explanation: The word "is" is not correct in this context. Instead, we should use the past tense form of the verb "stay," which is "stayed." Therefore, the correct sentence should be "Peter didn't know that Emma was visiting Warsaw today. He stayed at home."

9. I to London. I'll be back next month.
Correction: I am going to London. I'll be back next month.
Explanation: The word "to" is not correct in this context. Instead, we should use the present continuous tense of the verb "go," which is "am going." Therefore, the correct sentence should be "I am going to London. I'll be back next month."

10. He to restaurant. He'll be back at 10 o'clock.
Correction: He went to the restaurant. He'll be back at 10 o'clock.
Explanation: The word "to" is not correct in this context. Instead, we should use the past tense form of the verb "go," which is "went." Therefore, the correct sentence should be "He went to the restaurant. He'll be back at 10 o'clock."