A.手机
B.微波炉
C.电视机的遥控器
D.电饭煲
答案:D
He was about to say something more _____ a boy rushed in, gun in hand. [ ]
A. that
B. when
C. in case
D. while
将重30N的物体放在水平地面上。现用10N水平向右的力拉着该物体以1m/s的速度作匀速直线运动,则物体所受的摩擦力为______N,方向是_________。