滑车组的倍率表示滑车组（）的程度。
A.滑车数量
B.省力
C.绳索粗细
D.重力加速度
参考答案：A
We have done things we ought not to have done and ________ undone things we ought to have done.
A．left
B．leave
C．will leave
D．leaving
因为25比24大，所以25的因数的个数比24的多．…______．
