—Is that all?
—Yes. That's all ______ I want to take.
A:which
B:that
C:who
D:whose
Mr. Smith arrived at the station______.
关于双耳效应,下列说法正确的是( )
如图所示,在拉力F作用下,重300N的物体在水平桌面上以0.1m/s的速度做匀速直线运动,物体受到桌面的摩擦力为60N,若不考虑绳和滑轮重以及绳轮间摩擦力,则拉力F及其功率的大小分别为( )