问题
选择题
现有1000个氨基酸，其中氨基有1020个，羧基有1050个，则由此合成的4条多肽链中共有肽键、氨基、羧基的数目是[ ]
A．999、1016、1046
B．999、1、1
C．996、24、54
D．996、1016、1046
答案
答案：C
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现有1000个氨基酸，其中氨基有1020个，羧基有1050个，则由此合成的4条多肽链中共有肽键、氨基、羧基的数目是[ ]
A．999、1016、1046
B．999、1、1
C．996、24、54
D．996、1016、1046
答案：C
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| I first had physics lessons when I was in Grade Eight some years ago. In class, I 1 that there wasn't a Nobel (诺贝尔) Prize winner from China. That made me sad, and I decided to change (改变) it. 2 after that, I got up early in the morning. I turned on the light and took out a physics book. Then I started 3 quietly. I worked so hard because I had a great 4 - one day, I would be the first 5 person to win the Nobel Prize in physics. Later on, I found physics at school too easy for me. I wanted to lean 6 , so I made a reading plan and started to find answers to more difficult problems. Now I am a top student in physics. I won the first prize in the national physics competition last monh. And I am happy to be closer to my dream after a few 7 hard work. Of course, 8 I have some problems. My classmates always 9 me when they are talking about fashion (时尚) or pop stars, because I know 10 about them. "Well, that doesn't matter too much," I tell myself. "They don't know much about physics , but I won't laugh at them." | ||
| ( )1. A. joined ( )2. A. So ( )3. A. writing ( )4. A. dream ( )5. A. Chinese ( )6. A. much ( )7. A. weeks' ( )8. A. usually ( )9. A. depend on ( )10. A. anything | B. heard B. But B. reading B. idea B. Canada B. more B. months' B. always B. look at B. nothing | C. studied C. And C. thinking C. plan C. American C. most C. years' C. sometimes C. laugh at C. everything |