问题补充:
The president did much for world peace. That was he was awarded the Nobel Peace Prize.
A. when
B. what
C. because
D. why
答案:
A. when
B. what
C. because
(答案→)D. why
解析:句意:这个总统对世界的和平做出重大的贡献,那就是他为什么被授予诺贝尔和平奖的原因。A. when什么时候,B. what 什么,C. because因为,D. why为什么,所以选D。