氧乙炔焊接,点火后火焰很小且弱,原因是()
A.氧气不足
B.乙炔不足
C.氧气及乙炔均不足
D.乙炔气体阀门未开启
参考答案:C
用所给动词的正确形式填空。
1. If you want to learn English well, you should practise _________ (speak) English.
2. I spend two hours _________(do) my homework.
3. Hobo needs Eddie _________(carry) all the shopping bags.
4. I don't like _________(eat) hamburgers because they can make me fat.
5. My mother has a bad cold. She is __________(lie) in bed.
销售代表通过询问了解客户的一些基本背景情况进行辨别:基本业务应用情况、()、家庭成员业务应用状况。