Like racing cars that swerve and hit each other on a circular track, the moons' speed relative to each other is low because they travel in nearly the same orbit.
这有点像是突然转向的赛车在环形赛道上相撞，月亮们也在同一轨道公转，所以他们之间的相对速度很小。
2
If you must travel, inform a friend or relative of your proposed route and expected time of arrival.
如果必须出行，告知朋友或者家人你的计划路线和预计回来的时间。
3
Expedia's corporate travel business still is small relative to Expedia Inc. 's leisure and media businesses.