重型胎盘早剥与先兆子宫破裂共有的临床表现是
A．剧烈腹痛B．跨耻征阳性C．子宫呈板状硬D．出现病理性缩复环E．合并妊娠高血压综合征
参考答案：A
We ______ careful when we are walking across the road. There are too many vehicles now. [ ]
A. can be
B. may be
C. must be
加酸时应（）。
