挤压伤不常发生于（）。
A.肺
B.心
C.膈肌
D.空虚的膀胱
参考答案：D
You need _________warm clothes, or you'll catch a cold. [ ]
A. to wearing
B. wears
C. wearing
D. to wear
操作中的精馏塔，保持F、xF、q、R不变，增加W，则L/V( )，V'( )。
A．)不变
