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问题 单项选择题

人体不能合成维生素C，必需每日经食物摄取，因为人体内（）

A．糖醛酸途径活性太低

B．缺乏UDPG脱氢酶

C．缺乏古洛糖酸内酯氧化酶

D．缺乏古洛唐酸脱氢酶

答案

参考答案：D

填空题

根据句意及首字母或汉语提示完成句子。

1. It has been dry these days. You should w _____ the flowers as soon as possible.

2. Most of the w _____ animals living in the forest are dangerous.

3. Most of the students are a _____ the rule. They think teenagers shouldn't work at night.

4. We are proud of the four famous inventions in a _____ China.

5. I'm sorry I have l _____ my bike to Jim. You have to borrow one from others.

6. Would you like something _____ (别的) to drink?

7. We should go to school _____ (穿着) our school clothes on Monday.

8. I won't forget the _____ (经历) that I had last year.

9. Thanks for your _____ (建议). I'm sure they will be useful to my study.

10. At last he _____ (成功地) finished the work in time.
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单项选择题

正线直线无缝线路200km/h≥Vmax＞160km/h，道床顶面宽度（）m。

A、3.1m

B、3.4m

C、3.5m

D、3.6m
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