顺序练习
话题练习
题型练习
口语评分
写作评分
单科机考
全科模考
A.
It prevented high-speed motion of objects on Earth.
B.
It would only move if Earth moved.
C.
It was not affected by the motion of the Sun.
D.
It was not held down by any force.
正确答案:D
译文