题干
Finish your homework first,and then you'll watch TV for an hour.
A：can
B：be able to
C：able to
D：could
答案(点此获取答案解析）
B
Finish your homework first,and then you'll watch TV for an hour.
A：can
B：be able to
C：able to
D：could
个光滑的半球面内，如图所示。已知小球a和b的质量之比为
，细杆长度是球面半径的
倍。两球处于平衡状态时，细杆与水平面的夹角
是 （ )
