Английский язык Условные предложения

подставить глагол в правильную форму, чтобы получилось условное предложение
Fill in the gaps with the correct form of the verb in brackets.
1) If she (be) slimmer, she would be much more attractive.
2) If a fire starts, the alarm system
(go) off.
3) If the weather improves, I (go) for a walk.
there sim
4)If I (run) fast, I would have come first.
5) If I had known the answer, I
(make) a mistake.