1. Rewrite the sentences using the first or the second conditional. 1) I see Tom. I tell him the news. (if — first conditional) 2) You wait for me. I go to the market with you. (if — first conditional) 3) We have a yacht. We sail around the world. (if — second conditional) 4) Your room is tidy. You don’t look for your things. (if — second conditional) 5) They watch TV. She cleans the flat. (as soon as — first conditional) 6) Children don’t play with matches. A fire doesn’t break out. (if — second conditional) 7) He doesn’t read your e-mail letter. He doesn’t turn on his computer. (unless — first conditional) 8) We help her. She tells the truth. (if — second conditional) 9) They play a game of chess. Father returns home, (when — first conditional) 10) The train doesn’t arrive later. We don’t meet you here. (if — second conditional)

1) If I see Tom, I will tell him the news.
To rewrite the sentence using the first conditional, we need to use "if" followed by the present simple tense (do/does) and the future simple tense (will + base verb). In this case, the first part of the sentence "I see Tom" is in the present simple tense, so we need to use "will tell" for the second part.

2) If you wait for me, I will go to the market with you.
Again, we use "if" followed by the present simple tense and the future simple tense. In this case, the first part "You wait for me" is already in the present simple tense, so we just need to use "will go" for the second part.

3) If we had a yacht, we would sail around the world.
To rewrite the sentence using the second conditional, we need to use "if" followed by the past simple tense and the would + base verb. In this case, the first part "We have a yacht" is in the present simple tense, so we need to use "had" for the second part.

4) If your room were tidy, you wouldn't look for your things.
Using the second conditional again, we need to use "if" followed by the past simple tense and the would + base verb. However, for the second part, we need to use the negative form "wouldn't look" because the original sentence says "You don't look for your things."

5) As soon as they watch TV, she cleans the flat.
To rewrite the sentence using the first conditional, we need to use "if" or "when" instead of "as soon as" and use the present simple tense for both parts. In this case, we can use "When they watch TV, she cleans the flat."

6) If children don't play with matches, a fire doesn't break out.
Using the second conditional, we can rewrite the sentence using "if" followed by the present simple tense and the present simple tense for both parts. Since the original sentence says "A fire doesn't break out" in the second part, we keep it the same.

7) Unless he reads your e-mail letter, he won't turn on his computer.
To rewrite the sentence using the first conditional and "unless," we need to use "if" and the present simple tense for the first part, and the negative form of the future simple tense (won't + base verb) for the second part.

8) If we helped her, she would tell the truth.
Using the second conditional, we use "if" followed by the past simple tense and the would + base verb. In this case, the first part "We help her" is in the present simple tense, so we need to use "helped" for the second part.

9) When they play a game of chess, father returns home.
To rewrite the sentence using the first conditional and "when," we can use "When they play a game of chess, father will return home." Both parts use the present simple tense.

10) If the train doesn't arrive later, we won't meet you here.
Using the second conditional, we can rewrite the sentence using "if" followed by the present simple tense and the negative form of the future simple tense (won't + base verb) for both parts.