1\They have to explain ( )us the reason( )their doing so.A /;of Bwith;about C /;for D to ;for (D)

问题描述:

1\They have to explain ( )us the reason( )their doing so.A /;of Bwith;about C /;for D to ;for (D)

D两个固定词组
explain to sb 向某人解释
the reason for ...的原因
整个句子译为 他们必须要我们解释这样做的原因.