问题 单项选择题 A1/A2型题

在睾酮17位引入甲基可发生以下哪种变化()

A.改变了溶解度

B.改变了解离度

C.改变了分配系数

D.增加了脂溶性

E.增加了位阻

答案

参考答案:E

解析:因睾酮在体内易被代谢氧化,口服无效,在其结构的17位引入甲基,可获得甲基睾酮,甲基是一个烃基,在睾酮分子引入烃基,可使位阻增加,不易代谢,故甲基睾酮口服有效。

单项选择题
单项选择题

Robert Moody, 52, is an experienced police officer. Much of his work involves dealing with (16) and gang (团伙)problems in the schools of his community. Knowing that many kids often (17) trouble, he decided to do something about it. So in 1991 he began to invite small groups of kids to go fishing with him on his day (18) .

Those fun trips had a(n) (19) impact. A chance encounter in 2000 proved that. One day, (20) working security at a school basketball game, Moody noticed two young guys (21) . He sensed trouble between them. (22) one of them headed toward Moody and gave him a hug. "I (23) you. You took me (24) when I was in fifth grade. That was one of the (25) days of my life. "

Deeply touched by the boy’ s word, Moody decided to create a foundation (基金会)that (26) teenagers to the basics of fishing in camping programs. "As a policeman, I saw (27) there was violence, drugs were always behind it. They have a damaging (28) on the kids," says Moody.

By turning kids on to fishing, he (29) to present an alternative way of life, "When you’ re sitting there waiting for a (30) ," he says, "you can’t help but talk to each other, and such (31) can be pretty deep. "

"Talking about drugs helped prepare me for the peer(同龄人)pressures in high school," says Michelle, 17, who (32) the first program. "And I was able to help my little brother (33) drugs. "

Moody faces (34) in three years, when he hopes to run the foundation full-time. "I’ m living a happy life and I have a responsibility to my (35) to give back," Moody says. "If I teach a kid to

fish today, he can teach his brother to fish tomorrow. \

28().

A. impression

B. burden

C. decision

D. impact