问题
单项选择题
睾丸素在17α位增加一个甲基，其设计的主要考虑是（）
A.可以口服
B.雄激素作用增强
C.雄激素作用降低
D.蛋白同化作用增强
E.增强脂溶性，有利吸收
答案
参考答案：A
解析：
在对睾丸素进行结构改造中，发现在17位羟基的α面引入甲基，通过空间位阻可使17位羟基代谢比较困难，口服吸收稳定。故本题正确答案是a.
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睾丸素在17α位增加一个甲基，其设计的主要考虑是（）
A.可以口服
B.雄激素作用增强
C.雄激素作用降低
D.蛋白同化作用增强
E.增强脂溶性，有利吸收
参考答案：A
解析：
在对睾丸素进行结构改造中，发现在17位羟基的α面引入甲基，通过空间位阻可使17位羟基代谢比较困难，口服吸收稳定。故本题正确答案是a.
请阅读下面的这篇文章，根据所提供的信息，完成信息卡，把答案写在答题卷指定的位置上。 As a student, you must have homework every day. How do you deal with your homework? When do you usually finish your homework? Here is some advice for you to help you finish your homework well. Homework should be done as soon as you get home from school. If you have after-school activities, the homework should be done first. At the same time, it is fine to allow for a snack break and also to allow for stretching(伸展) breaks. Also, you should remember that it is your duty to do your homework. Don’t depend on Mum and Dad for help. Please try to find the answer yourself because you will learn much more that way. When you have a question, especially something about a science or maths, don’t always turn to your teacher! It is a good idea to try to find the answer yourself. If this doesn’t work, you can also look at your textbooks carefully. They may help you understand the problem. Finally, while doing homework, don’t think about or do other things. Keep working. Setting a time limit(限制) often helps with this. Different ages decide different amounts of time. 10-15 minutes is good for a child that’s aged 6-8. A time of 20-30 minutes is about right for a child aged 9-12. Kids can keep studying for 30-45 minutes at the ages of 13-15. This, of course, depends on your ability to pay attention and stay on tasks. Information Card
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