题干
The workers were made from morning to night in the past.
A：worked
B：to work
C：work
D：working
答案(点此获取答案解析）
B
The workers were made from morning to night in the past.
A：worked
B：to work
C：work
D：working
，在A处放置一个质量为m的物体，现绕O点缓缓抬高A端，直到当木板转动到与水平面成α角的过程中，物体始终处于静止，在整个过程中（ ）