It’s very easy for us asleep with relaxing music going on when we’re tired.A. fallB. falli

问题补充：

It’s very easy for us asleep with relaxing music going on when we’re

tired.

A. fall

B. falling

C. to fall

D. fell

答案：

A. fall

B. falling

(答案→)C. to fall

D. fell

解析：句意：当我们劳累时，伴随着令人放松的轻音乐睡觉对我们来说很容易。强调句式， It is adj for sb to do sth，做某事对某人来说怎么样。本句中it是形式主语，指代后面不定式内容做形式主语。不定式做主语表示具体的将要发生的动作。故选C。