对于开口微孔材料，当其孔隙率增大时，材料的密度（）。
参考答案：
不变
用括号里所给单词的适当形式填空
1. I’m looking forward to (see) you soon.
2. My uncle (work) in that restaurant.
3. A (care) driver often causes (引起) a traffic accident.
4. There (be) heavy rain tonight.
5. Table tennis is (popular) than running.
现代企业
