在各类泵中，最适宜输送黏稠液体的泵是（）。
A.齿轮泵
B.往复泵
C.真空泵
D.离心泵
参考答案：A
You can't imagine the difficulty he ________onto the cliff and saving the boy in trouble.[ ]
A. had to climb
B. had climbed
C. had climbing
D. had on climbing
下面哪些情况常需手术处理（）。
A.儿童生长性颅骨骨折
B.儿童凹陷骨折，骨折下陷大于1.0cm
C.成人凹陷骨折，深度大于1.0cm，伴有静脉窦损伤
D.洞型凹陷骨折
E.粉碎性凹陷骨折
