2013年,“嫦娥三号”将把我国自主研制的“中华牌”月球车送上月球。“中华牌”月球车装有六个车轮,车轮上刻有螺旋形花纹是为了()
A:增大摩擦
B:减小摩擦
C:增大压力
D:减小压力
You can't watch TV until your homework is ____ (finish).
种子结构中哪个部分实际上就是幼小的生命体( )
The shopkeeper did not want to sell for he thought was not enough.