Question

Last month 3 people got injured in a gas explosion,        has not been discovered yet.

A．whose cause

B．the cause of that

C．which cause

D．the cause

Answer 1

A

试题分析：上个月3个人在煤气爆炸中受伤，爆炸的起因还没有发现。先行词是a gas explosion，定语从句中cause缺少定语，用whose引导定语从句，或the cause of which，选A。