月经先期与下列哪两项并见时,有发展为崩漏之虞()
A.月经量少
B.经间期出血
C.月经过多
D.经期延长
E.痛经
参考答案:C, D
“How does he often go to school?” “ ”
A. By a bike B. By his bike C. On his bike
如图所示,集气瓶内充满某混合气体,置于光亮处,将滴管内的水挤入集气瓶后,烧杯中的水会进入集气瓶,集气瓶内气体是
①CO、O2; ②Cl2、CH4; ③NO2、O2; ④N2、H2
A.①②
B.②④
C.③④
D.②③