下列关于牛顿第一定律的说法中,正确的是() A . 必须有力作用在物体上,物体才能运动。 B . 月球车在月面上运动时没有惯性 C . 踢出去的足球由于惯性还能继续向前运动一段时间 D . 战斗机作战时要抛掉副油箱是为了减小惯性 答案:C,D13、Schools across China are expected
to hire 50,000 college graduates this
year as short-term teachers, almost three
times the number hired last year, reduce
unemployment pressures.
A. help
B. to have helped C.
to help D. having helped