It was repairing the old clock that the old man spent the whole morning at home.
问题描述:
It was repairing the old clock that the old man spent the whole morning at home.
为什么用REPARING
答
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