题干
A month had passed, but the government didn't find the________of the mine accident.
A：reason
B：result
C：effect
D：cause
答案(点此获取答案解析）
D
A month had passed, but the government didn't find the________of the mine accident.
A：reason
B：result
C：effect
D：cause
，
，则角A=（ ）.