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问题 单项选择题 A型题

喷他佐辛很少引起成瘾是因为（）

A.拮抗μ受体

B.拮抗K受体

C.拮抗α受体

D.拮抗δ受体

E.拮抗DA受体

答案

参考答案：A

解析：喷他佐辛很少引起成瘾，因喷他佐辛是阿片受体的部分激动剂，现知阿片受体分为μ、K、δ、σ四种亚型，μ受体与脊髓的水平镇痛和成瘾有关；K受体与脊髓水平镇痛和镇静有关；σ受体与脊髓的水平镇痛和欣快镇静有关；δ受体与烦躁不安和幻觉有关。喷他佐辛拮抗μ受体，使成瘾的发生率大大降低，因而，喷他佐辛已被列入非麻醉品。

单项选择题

How to protect children Web fans from unsuitable material on-line while encouraging them to use the Internet has long been discussed in the US.
For some parents, the Internet can seem like a jungle, filled with danger for their children. But jungles contain wonders as well as dangers and with good guides, some education, and a few precautions, the wilds of the Internet can be safely navigated. "Kids have to be on-line. If we tell our kids they can’t have access to the Internet, we’re cutting them off from their future, " said an expert.
Most kids have started to use search engines. Many of them are great for finding tons of interesting Internet sites, and they can also locate places where you might not want your kids to go. There are search engines designed just for kids. A certain software contains only sites that have been selected as safe. The most popular way to limit access would be to use what is known as a "content screener". But this can’t be wholly reliable, and the best thing parents can do is to talk to their kids and let them know what is OK or not OK to see or do on the Internet. Another way is that mum or dad is nearby when the child is surfing the Internet.
A few other tips
·Don’t put the PC in a child’s room but keep it in an area where mum or dad can keep an eye on things. That also makes the Internet more of a family activity.
·Ask your child what he or she has been doing and about any friends they make on-line.
·Tell your child not to give on-line strangers personal information, especially like address and phone number.
·And tell your children never to talk to anyone they meet on-line over the phone, send them anything, accept anything from them or agree to meet with them unless you go along.

According to the passage, we can infer that ______.

A. soft wares fit for children want programming
B. a child who is on-line is in danger
C. Internet is a jungle full of danger
D. Internet contains a lot of harmful sites
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单项选择题

监理人由于非自己的原因致使暂停或终止监理服务，应当立即通知（）。

A.施工单位

B.设计单位

C.委托人

D.采购单位
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