拆除旧电梯时，严禁先拆（）.
A.自动门机
B.轿顶
C.限速器
D.电源开关
参考答案：C
When my grandfather retired(退休) at the age of 60, he took a sea ________ around the world, which had been his dream since his childhood.
A．travel
B．trip
C．voyage
D．journey
是社会发展的决定力量。（）
A．生产关系
B．经济基础
C．上层建筑
D．生产方式
