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听力原文：M: What was Professor Calhourn saying about the lecture series on alternative forms of energy when I walked in late? I had trouble with my car again. W: The first lecture's tonight. All second and third year students are invited to buffet dinner tonight be fore it starts. Then at 6:30, the speaker will begin her talk on solar energy. M: Can nonengineering students attend all four weeks of the series? W: No, they can only go to this week's lecture. During the next three weeks, the admission will be restricted to engineering students. M: Oh, then I'm going to try to make it tonight. Can I give you a ride over there? W: No, but thanks anyway. Wait a minute, didn't you say that you are having car trouble lately? Let me give you a ride. (20)A.
Admission forms.
B.
Solar energy.
C.
Auto maintenance.
D.
Course requirements for engineers.
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【单选题】已知四台显微镜的目镜和物镜的倍数如下，在观察洋葱表皮细胞时，视野中细胞数目最多的显微镜是（ ）。 显微镜序号 目镜 物镜 1 5X 8X 2 10X 40X 3 15X 10X 4 20X 15X
A.
1
B.
2
C.
3
D.
4
【单选题】已知显微镜目镜视觉放大倍率 τ =15,物镜垂轴放大率β=2.5,共轭距L=180mm,问显微镜总放大率为()。
A.
-37.5
B.
37.5
C.
45
D.
-45
【单选题】用显微镜观察标本时，已知显微镜中观察到的物像的截面积被放大了10000倍，则选用的目镜和物镜组合是 [ ]
A.
目镜(10×)和物镜(10×)
B.
目镜(10×)和物镜(40×)
C.
目镜(100×)和物镜(100×)
D.
目镜(40×)和物镜(40×)
【简答题】已知显微镜目镜Γ=15，问其焦距为多少?物镜β=2.5，共轭距L=180mm，求其焦距及物、像方距离。问显微镜总放大率为多少?总焦距为多少?
【简答题】已知显微镜目镜的焦距为5cm，物镜的焦距为2mm，要获得400倍的放大倍数，光学筒长应为 。
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