防止水泵叶轮的特点是（）。
A.叶轮大，叶片多
B.叶轮小，叶片少
C.叶片厚度大，叶片少
参考答案：C
本例的骨盆诊断是()。
A．扁平骨盆
B．中骨盆狭窄
C．漏斗骨盆
D．均小骨盆
E．畸形骨盆
The Browns sent lots of invitations for their party. But because of the improper time, few people ________ it.
A．attended
B．accepted
C．received
D．donated
