Решение:
- If they do not eat well, they are not healthy.
- If I go on a ferry, I always feel sick.
- I feel very good the following day if I have enough sleep.
- If I do not know a word, I look it up in my pocket dictionary.
- They play video-games if they do not have any homework.
- If you bring the temperature down, this water turns into ice.
- She likes to visit the museums if she is in a new country.
- Vasya always buys expensive clothes if he goes shopping.
- Tamara, our maths teacher, gets angry if we do not work hard enough.
- If you press this button here, the light goes on.
Ответ: 1. do not eat, are not; 2. I go; 3. feel, have; 4. I do not know, look; 5. do not have; 6. turns; 7. likes, is; 8. buys, goes; 9. we do not work; 10. press, goes.