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问题 单项选择题 A1/A2型题

最适合于时间分辨荧光免疫测定的荧光物质（）

A.异硫氰酸荧光素

B.四乙基罗丹明

C.四甲基异硫氰酸罗丹明

D.藻红蛋白

E.镧系稀土元素（Eu3+）

答案

参考答案：E

解析：Eu3+螯合物激发光波长范围宽、发射光波长范围窄、荧光衰变时间长，最适合于时间分辨荧光免疫测定。

阅读理解
Here are two letters to George and his answers.
 Dear George,
I’m fourteen and I’m much shorter for my age. What’s worse, I’m very fat. I want to lose weight to be 55 kg and to be taller and then I can go to the school basketball team and enjoy myself. Can you help me?
Bob
 Dear Bob,
Don’t warry if you’re shorter than your friends. Teenagers（青少年）grow at different times.
It doesn’t matter how heavy you are. You are still the same person. Plan your meals with your mum, and she can help you lose weight. Also, try to take more exercise.
George
 Dear George,
I’m learning French but I don’t get good marks. I don’t know why. Sometimes I want to give up. But I know I shouldn’t because languages are going to be very important. What should I do?
Alice
 Dear Alice,
You are right. You shold never give up, and I’m sure that you’ve mde more progress than you think. You can talkto your teacher and ask her what you should do to get a better grade. Talk to your friends who are good at French. Find something that helps you.
George
小题1:According to the letters, we now that George is ______.
A．a teacherrB．a doctor
C．a person who can give others adviceD．Bob and Alice’s friend
小题2:The weight of Bob is ______ now.
A．about 50 kgB．55 kgC．more than 55 kgD．less than 55 kg
小题3:Alic is worring about ______.
A．her friendsB．her marksC．her heightD．her weight
小题4:Bob should ______ accroding to George’s letter.
A．take more exerciseB．talk to his friends
C．join a basketball teamD．learn some French
小题5:George advises Alice to talk to ______ for help.
A．her motherB．her teacherC．Bob’s teacherD．Bob’s friends
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单项选择题

进气道的总压恢复系数的大小反映了（）的大小.

A.流动损失

B.压力变化

C.气流速度变化

D.流场均匀程度
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