使用换热器的注意事项有()个方面。
A.两
B.三
C.四
D.五
参考答案:B
查处酒后驾驶采用的“便携式测量仪”是以燃料电池为工作原理,在酸性环境中,乙醇被氧化为X,其中一个电极的反应式为:CH3CH2OH-2e-=X+2H+.下列说法中正确的是( )
A.燃料电池属于二次电池
B.另一极的电极反应式为:O2+4e-+2H2O=4OH-
C.乙醇在正极发生氧化反应
D.电池总反应为:2CH3CH2OH+O2→2CH3CHO+2H2O
用所给词的适当形式填空。
1. We all like________ (play) soccer.
2. I find he________ (watch) TV in the next room.
3. The students should practice________(write) and reading every day.
4. Mr. Hu loves________ (take) a walk near the river.
5. There ________ (be) a few people in the park.