碰撞力的三要素（）
A. 大小
B. 方向
C. 作用点
D. 面积
车架损伤的形式有：（）
A. 上下变形
B. 左右变形
C. 凹缩变形
D. 扭曲变形
Modern science has given clear evidence __________ smoking can lead to many diseases.
A. what
B. when
C. that
D. where
__________ the English evening will be held has not yet been announced.
A. Where
B. Who
C. What
D. Whom
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