— Did Eric go swimming yesterday? — _________. He went to the movies with Mark.
A:Yes, he did
B:Yes, he does
C:No, he didn't
D:No, he doesn't
We don't think it's good to stay_____ late to play computer games.
判断对错.
两条直线相交组成的4个角中如果有一个角是直角,那么其他3个角也是直角.
____
质量m=2kg的物体静止在水平地面上,它与地面间的动摩擦因数μ=0.4,一个F=10N水平恒力作用在物体上,使物体在水平地面上运动.F作用4s后撤除.(取g=10m/s2)则: