急性胎儿窘迫早期胎心音为
A．150～160次/分B．>160次/分C．<120次/分D．120～160次/分E．<100次/分
参考答案：B
They had an accident on the road and didn't ______ at their hotel until after midnight. [ ]
A. check out
B. check on
C. check in
D. check over
机组热态启动时应注意什么问题？
