They paid ______ money for the machine than I had expected. [ ]

A. much

B. fewer

C. many

D. more

下列说法中正确的是 [ ]

A. 施力物体同时也是受力物体

B．空中飘落的树叶不受任何力作用

C. 在地面上滚动的球受到向前的力

D．浮在水面上的木块不受重力作用