下列属于混凝土外加剂的是( )。
A．减水剂
B．引气剂
C．缓凝剂
D．防冻剂
E．早强剂
参考答案：A,C,D,E
The difficulty she had _____ her three children was solved by the local government.[ ]
A. feeding
B. fed
C. to feed
D. feed
一初产妇，宫口开全1.5小时，胎头已达盆底，LOT位持续，应如何（）。
A.人工协助逆时针转90°
B.行会阴后一斜切开术
C.静点缩宫素
D.人工顺时针转90°
E.顺其自然
