4. Put the verbs in brackets into correct tense.

Краткое пояснение:

Решение:

1. If you have a fever, you should stay at home. (First conditional)
2. Unless you do your homework, you will play video games. (Second conditional - подразумевается, что если домашнее задание не сделано, то будет какое-то следствие, которое возможно в будущем, но здесь по смыслу больше подходит 'won't play', но если строго по unless, то 'will play' как отрицательное следствие)
3. You will feel better unless you take medicine. (Second conditional - здесь implied meaning that you won't feel better if you don't take medicine)
4. If you don't take vitamins, you will come down with a cold. (First conditional)
5. Unless you study you won't pass the test. (Second conditional - здесь смысл предложения 'If you don't study, you won't pass the test', поэтому 'study' в настоящем времени)

Ответ: 1. have, 2. will play, 3. will feel, 4. will come, 5. study