为体现“绿色奥运”“科技奥运”，2008年北京奥运会出现了中国自己生产的燃料电池汽车，作为马拉松领跑车和电视拍摄车，该车装着“绿色心脏”--质子交换膜燃料电池，其工作原理如图所示，下列叙述正确的是
A. 通入氧气的电极发生氧化反应
B. 通入氢气的电极为正极
C. 总反应式为O2+2H2
2H2O
D. 正极的电极反应式为O2+4H++4e-====2H2O
答案：D
| 阅读短文，完成各题。 | |
is at school. A thief (贼) comes into John's room. He wants to steal (偷) something. A voice comes. " Hello! I can see you! " The thief puts the things on the floor and runs away (逃跑). 根据短文内容，判断句子对(√)错(×)。 ( ) 1. John is a doctor (医生). ( ) 2. John has some birds. ( ) 3. The thief wants to take some things away (带走一些东西) from the room. ( ) 4. The bird can say some Chinese (汉语). ( ) 5. The thief sees John and goes away (走开). 根据短文内容，选出正确答案。 | |
| 6. John's bird is very ____________. | |
[ ] | |
| A. thin B. big C. nice | |
| 7. The bird can say " ____________! " | |
[ ] | |
| A. Look! A thief B. Bye-bye C. Hello! I can see you | |
| 8. One day a ____________ comes into John's room. | |
[ ] | |
| A. student B. thief C. farmer | |
| 9. ____________ drives away (赶跑) the thief at last (最后). | |
[ ] | |
| A. The bird B. John's father C. John |