下列易导致产后尿潴留的原因是（）。
A.产后活动减少
B.产后腹压降低
C.产后会阴部疼痛
D.产褥感染
E.产后出血
参考答案：C
(2013·高考天津卷)If he had spent more time practising speaking English before，he________ able to speak it much better now.
A．will be
B．would be
C．has been
D．would have been
高空焊割作业应选哪种安全带（）
A、尼龙
B、帆布
C、标准的防火安全带
