Many young people in the West are expected to leave could be life' s most important decisi

问题补充：

Many young people in the West are expected to leave could be life s most important decision -- marriage -- almost entirely up to luck.

A. as

B. that

C. which

D. what

答案：

A. as

B. that

C. which

(答案→)D. what

解析：宾语从句中缺少主语，这里要用what。