如果刹车失灵，那会很危险。

It would be dangerous if the brakes ___fail.

如果关键部件失灵，整个系统可能会关闭。

If a critical component ___fails, the entire system might shut down.

停电期间，旧发电机失灵，使情况恶化。

The old generator ___failed during the blackout, worsening the situation.