机械密封泄漏允许轻质油不超过()滴/分。
A.20
B.15
C.10
D.以上都不对
参考答案:C
4. Have you heard of the town when they built the dam?
A.submerge
B.submerging
C.being submerged
D.submerged
早产儿的特点是()
A.出生体重大于2500g
B.哭声轻柔,有一定肌肉张力
C.耳壳软骨按压后很快恢复
D.足底的纹理难以看清
E.男婴睾丸下降