题干
Xia Peng, an English educator, pointed out ______ critical thinking is added to his or her English speech, the student will be outstanding.
A：that whether
B：what that
C：that if
D：where that
答案(点此获取答案解析）
C
的光滑斜面上，由底端向顶端做匀加速运动。当物体运动到斜面中点时，去掉推力，物体刚好能到达顶点，则推力的大小为（ ）