问题
选择题
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
答案
答案：A
题目分析：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。