问题 单项选择题

视网膜内屏障的构成,以下说法正确的是()

A.由视网膜色素上皮组成

B.介于视网膜与玻璃体之间

C.由视网膜内界膜组成

D.阻挡脉络膜血管内的血液成分渗漏至视网膜内

E.由视网膜血管内皮间的连接复合体组成

答案

参考答案:E

解析:视网膜血管内皮细胞间的连接复合体构成血-视网膜内屏障,血-视网膜外屏障位于色素上皮外。视网膜屏障能阻挡视网膜血管内和脉络膜血管内的血液成分和大分子物质进入视网膜。

完形填空

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

May the first is an important date in the college admission process in the United States.This is the last day for high school seniors to accept or reject offers of admission in the fall.But according to a recent report, there is a great change.Acceptance rates at the top colleges this year were lower than ever.   小题1:  

These days, college applicants are applying to more colleges because online and common applications make the process easier. 小题2:  On the other hand, deciding students for top colleges to accept can be difficult because it takes much time.Students may not like being put on waiting lists.Also, common colleges work more to get the students they accept to accept them.Some colleges hold visiting days that offer a chance to attend classes and stay overnight.Some universities send gifts. 小题3:    

For many families, the most important thing colleges can do is show them the money, especially this year; the weak economy makes parents nervous. 小题4: The recent problems that spread from the housing market to credit markets have even affected student’s loans.So lately, top schools have to spare lots of money to increase their financial aid for students.

  小题5:    The Education Department expects the number of high school graduates to start to go down.This will happen as the last of the children of the baby boom generation finishes high school.The number is not expected to start rising again until 2015.

A.Besides, top colleges are facing changes in the population.

B.What contributes to it?

C.But a mistake can be costly if it happens.

D.But top colleges ignore them.E.They have international students who know English.

F.It can mean several acceptances to choose from.

G.They cannot afford college as planned.

单项选择题 A1/A2型题