问题
选择题
淀粉酶能催化淀粉水解，但不能催化蛋白质水解。该事实说明[ ]
A．酶具有专一性
B．酶的化学本质是RNA
C．酶具有高效性
D．酶的作用受温度影响
答案
答案：A
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淀粉酶能催化淀粉水解，但不能催化蛋白质水解。该事实说明[ ]
A．酶具有专一性
B．酶的化学本质是RNA
C．酶具有高效性
D．酶的作用受温度影响
答案：A
| 阅读理解。 | ||||||||||
| Mr and Mrs Chen went to Europe for a holiday. They visited Copenhagen, the capital (首都)of Denmark, and stayed there for three days. While they were in Copenhagen, they went to a famous park called the Tivoli. Their children bought huge ice creams and enjoyed themselves in the park. Mary Chen bought an unusual postcard. There is a picture on the card. In the picture a policeman is stopping the traffic. Why is the policeman stopping the traffic? There is not as much traffic in Copenhagen as in Singapore. Some of the streets are closed to vehicles (机动车). They are called"Walking Streets" because people can walk along them safely. Mary wrote the address of her cousin on the back of the postcard. Then she wrote: Dear Sue, We arrived at Copenhagen last night. Daddy took us to the Tivoli Park this afternoon. I bought a chocolate ice-cream but it was so big that I couldn't eat it all! Compared with Singapore, Copenhagen is just as clean but it is not as noisy and busy. Some of the shopkeepers speak English here, and I have seen four Chinese restaurants already. No more space now. Please give our love to all the family. love, Mary | ||||||||||
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