掌握曲线运动动画的基本要领有（）三种。
A.物体质量大小
B.主动力与被动力
C.运动方向
D.顺序朝前推进
E.物体受力大小
参考答案：B, C, D
-How do you like our town ?
-_________. It’s worth visiting a second time .
A．You’ve got it
B．It’s your turn
C．It’s fascinating
D．Up to you
Which magnetic compass corrector（s）can be set while the vessel is on a heading of magnetic north or magnetic south（）.
A.Quadrantal spheres
B.Heeling magnets
C.Flinders bar
D.Fore-and-aft magnets
