220V直流电压范围？
参考答案：
220V直流系统电压正常应保持在220±10V。
用 before long或 long before填空。
1. _____ pyramids were built, and we'll go to visit them ____.
2. My friend,Jim Green,will come back to Beijing ____.
3. It was not _____ everyone came to know her.
4. ____ he had to return to the village where he once lived ____ .
关于妊娠晚期出血的处理，下述哪项是不正确的（）
A.前置胎盘禁做肛查
B.子宫胎盘卒中，出血不止，应切除子宫
C.妊娠合并子宫颈癌临产，不论哪期都行剖宫产
D.妊娠合并宫颈息肉，可以 * * 分娩
E.帆状胎盘血管前置出现孕晚期出血，可 * * 分娩
