fall|fallen|falling|fell

他摔得很重，腿断了。

He ___fell badly and broke his leg.

到冬天时，所有叶子都从树上掉落了。

By winter, all the leaves had ___fallen off the trees.

我在看电视时在沙发上睡着了。

I ___fell asleep on the sofa while watching TV.

医生说我需要多休息，这样我的血压才会降下来。

The doctor said I need more rest so my blood pressure will ___fall.

预计今晚气温将降至冰点以下。

Temperatures are expected to ___fall below freezing tonight.

伦敦桥正在倒塌。

London Bridge is ___falling down.