Classify the following words into four categories.

1. If he's h angry, is face always goes bright red. Present Simple- действие выполняет he, третье лицо единственного числа, к глаголу - подлежащему + окончание -s.

2. The radio doesn't work if the batteries are flat.

3. If there are only a few students we usually closes one of the classes.глагол to be изменится на are во множественном числе.

4. The machine doesn't work if it doesn't have enough oil.

5. If a balloon is filled with hir air, it rises.

6. If water boils, it changes into steam. Water - заменим местоимением it - третье лицо единств. числа, к глаголу сказуемому + окончаниe - S.

7. The machine stops automatically if something goes wrong.

8. Our Math teacher gets angry if we don't work hard enough.

9. If you bring the temperature down, this water turns into ice.

Объяснение: