产褥感染的诱因中错误的是( )
A.产后出B.产褥期性交C.巨大儿D.孕期贫血及营养不良E.前置胎盘
参考答案:B
解析: 临近预产期性交是产褥感染的原因。
Mr. Black would rather __________than _________on Christmas eve because of the crazy spray snow fight everywhere.
A.stay at home, to go out
B.stay at home, go out
C.to stay at home, go out
D.to stay at home, to go out
管路系统的特性曲线是随着()的增加而上升。
A、流量
B、扬程
C、轴功率
D、效率