车轴齿轮箱是用滚动轴承支承在车轴上,车轮转动时,由于受轮对牵引力的反扭矩作用,齿轮箱有向下转动的趋势,因此,车轴齿轮箱必须用()来支撑,使它不能转动。
参考答案:平衡杆
_____ your brother _____ eggs every day? [ ]
A. Do have
B. Does have
C. Does has
D. Do has
—What’s the noise outside?
—Some children_____ hide-and-seek in the yard.
A.were playing
B.are playing
C.have played
D.played