风桥是矿井通风设施中的一种,其作用是()。
A.隔断风流
B.调节风量
C.使进回风路相交处的进风与回风互不混合
参考答案:C
无排卵功血、黄体功能不全、子宫内膜不规则脱落的诊断性刮宫时间?
Why didn't you ask for help,____ trying to do it on your own? [ ]
A. rather than
B. other than
C. more than
D. less than