题目

It was repairing the old clock that the old man spent the whole morning at home.
为什么用REPARING

提问时间：2020-08-02

答案

it指代的是the old man spent the whole morning at home.
所以题目变为 The old man spent the whole
morning ( ) the old clock at home.
spend (on) doing sth
所以：REPARING