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【单选题】
下列关于相差显微镜说法错误的是()A.
基本原理是以样品密度差别为基础，将光程差转换成振幅差，形成明暗区别
B.
样品不需要染色
C.
可以观察活细胞
D.
可以对细胞的生物大分子进行定位和定性分析
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参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】在频率分布直方图中,下列说法正确的是
A.
每个小方块的高度值表示该组的频率
B.
所有小方块的面积之和为1
C.
Excel可以直接画出标准的频率分布直方图
D.
频率分布直方图与频数分布直方图是同一张统计图
【单选题】关于频率分布直方图,下列说法正确的是
A.
直方图的高表示某数的频率
B.
直方图的高表示该组上的个体数与组距的比值
C.
直方图的高表示该组上的总体数与组距的比值
D.
直方图的高表示该组上的个体在样本中出现的频率与组距的比值
【单选题】听力原文：W: We'd like to order now. M: Yes? What would you like to begin with? Where does this conversation most probably take place?
A.
In a hospital.
B.
In the army.
C.
In a restaurant.
D.
In the classroom.
【简答题】塑料加工助剂主要可分为加工改性助剂、稳定化助剂和 .
【单选题】What does 'You begin to worry that fights of fancy might become one way' mean?
A.
You begin to worry that you'll never be a useful member of the society again.
B.
You begin to worry that you'll never be able to find a job again.
C.
You begin to worry that you'll never be able to face the reality.
D.
You begin to worry that you'll never be able to see your relatives again.
【单选题】听力原文：W: Before we begin the tour of the factory, do you have any more questions? M: Yes, I have one. I' d like to know the exact difference between crystal and glass. W: Well, real crystal is generall...
A.
at an industrial site
B.
at a department store
C.
in a classroom
D.
in a skyscr
【单选题】At a dinner, you can begin to eat
A.
when the guests sitting beside you begin.
B.
when the hostess says, 'Let's begin.'
C.
when the main course is served.
D.
when the hostess picks up her own spoon or fork..
【单选题】Before you begin writing your paper, please write ------__________ first. Then we can have a better idea about what you are going to talk about.
A.
an origin
B.
a detail
C.
an example
D.
an outline
【单选题】材料在振动或冲击作用下,能吸收较大能量,并产生较大变形而不突然破坏的性质称为韧性。 下列材料中不属于韧性材 料的是()。
A.
素混凝土
B.
钢材
C.
木材
D.
橡胶
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