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问题 单项选择题 A1/A2型题

具备何种特性的麻醉药与镇痛药较易通过胎盘（）。

A.脂溶性高，电离度高

B.脂溶性低，电离度低

C.脂溶性高，电离度低

D.脂溶性低，电离度高

E.水溶性高，电离度低

答案

参考答案：C

解析：胎盘为脂质屏障，具有蛋白质性质，凡是脂溶性高、电离度低的物质均容易通过。

完形填空

Healthy teeth are important in many ways. For example, when we get our pictures taken, everyone says “Say cheese!” So we open our mouth and show our teeth.

小题1:Strong and healthy teeth help us chew the right food to grow. They also help us speak clearly and look our best. 小题2:我们必须照顾好我们的牙齿。What should we do to protect our teeth?

First, we should brush them at least twice a day—after breakfast and before bedtime. We should brush all of our teeth, not just the front ones. 小题3: We should spend at least 3 minutes each time brushing teeth.

小题4:一年看两次牙医也很重要。Besides checking for disease, the dentist will help keep our teeth extra clean.

小题5:We also need to be careful about what we eat and drink. Remember to eat more vegetables and fruit and drink more water. Of course, don’t forget to smile!
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单项选择题 A1型题

竞争性抵制剂与酶结合的部位是（）。

A.中间产物

B.活性中心底物结合基团

C.酶活性中心外的必需集团

D.全部集合

E.中间产物及中心集团
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