某化合物由A、B两元素组成，已知A、B两元素质量比为7∶4，原子量比为7∶8，则

I didn’t get up earlier as usual last Sunday． In the morning having finished my homework, I do some washing．Then I telephoned one of my classmates and invited them to see a film．But unfortunately, when we got to the cinema, we founded all the tickets had sold out．We had to go back to school or play football．After that, we were about to go to home when we saw our English teacher, Mr．Li, coming towards us．Tom and I asked him some questions about what to learn English well．He told us we had made great progresses in English．He also suggested that we read more and write more．We promised him that we would follow our advice

仪器仪表的检定一般分为（）、（）、验收检定三种情况。

子宫肌瘤常见的临床表现是（）

A.月经量多

B.不孕

C.慢性贫血

D.经期延长

E.以上都是

氯吡格雷（）。

A．扩张冠状动脉，减慢心率

B．减慢心率，降低血压，减少心肌氧耗量

C．扩张冠脉，解除冠脉痉挛

D．抗血小板聚积，防止血栓形成

E．扩张动静脉，降低心脏前后负荷

工程上常用的投影方法有（）、（）、标高投影法和透视投影法。