三元复合驱中,由于pH值急剧(),导致油层水中急剧结垢。
A、下降
B、升高
C、持平
D、波动
参考答案:B
用所给词的适当形式填空。
1. I spent an hour (mend) my bike.
2. I (be) to Beijing twice before.
3. I am sorry (trouble) you.
4. The old woman (die) for about ten years.
5. Would you mind (open) the door?
6. Two weeks (be) a long time.
7.Would you like (come) with me?
8. He has something interesting (tell) you.
9. My mother hates (travel) by plane.
10. We went to the zoo (watch) the animals yesterday.
我国工业的空间分布?