工业上生产尿素的主要原料是（）和（），它们分别是（）的主副产品。
参考答案：液氨；气体二氧化碳；合成氨车间
用所给单词的适当形式填空
1. It's hard (stop) riding cars.
2. _ ___ ( recycle) paper is really hard.
3. The trees can stop the wind (move) towards the rich land.
4. I stopped (use) napkin last year.
5. She remembered (lock) the door, but she didn't.
二进制数345对应的十进制数是
A．25
B．65
C．35
D．32
