题目内容
（请给出正确答案）
A.fA=2
B.fA=3
C.fA=4
D.fA=5
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更多“根据以下材料回答第 78～80 题： 某单因子试验，因子A有3个水平，每个水平做5次重复试验，则 第”相关的问题
Each advance in microscopic technique has provided scientists with new perspectives on the function of living organisms and the nature of matter itself. The invention of the visible-light microscope late in the sixteenth century introduced a previously unknown realm of single celled plants and animals. In the twentieth century, electron microscope have provided direct views of viruses and minuscule surface structures. Now another type of microscope, one that utilizes X rays rather than light or electrons, offers a different way of examining tiny de tails; it should extend human perception still farther into the natural world.
The dream of building an X-ray microscope dates to 1895; its development, however, was virtually halted in the 1940's because the development of the electron microscope was progressing rapidly. During the 1940's, electron microscopes routinely achieved resolution better than that possible with a visible-light microscope, while the performance of X-ray microscopes resisted improvement. In recent years, however, interest in X-ray microscopes has revived, largely because of advances such as the development of new sources of X-ray illumination. As a result, the brightness available today is millions, of times that of X-ray tubes, which, for most of the century, were the only avail able sources of soft X-rays.
The new X-ray microscopes considerably improve on the resolution provided by optical microscopes. They can also be used to map the distribution of certain chemical elements. Some can form. pictures in extremely short times; others hold the promise of special capabilities such as three-dimensional imaging. Unlike conventional electron microscopy, X-ray microscopy enables specimens to be kept in air and in water, which means that biological samples can be studied under conditions similar to their natural state. The illumination used, so-called soft X rays in the wavelength range of twenty to forty angstroms (an angstrom is one ten-billionth of a meter), is also sufficiently penetrating to, image intact biological cells in many cases. Because of the wavelength of the X rays used, soft X-ray microscopes will never match the highest resolution possible with electron microscopes. Rather, their special properties will make possible investigations that will complement those performed with light-and-electron-based instruments.
What does the passage mainly discuss？
A．The detail seen through a microscope.
B．Sources of illumination for microscopes.
C．A new kind of microscope.
D．Outdated microscopic techniques.
A．确定原因时应有独立的见解，考虑充分
B．确定原因时应通过大家集思广益，充分发扬民主，以免疏漏
C．确定原因，应尽可能具体
D．有多少质量特性，就要绘制多少张因果图
E．验证
A．关注程度低于A类和B类的一类不合格
B．认为关注程度比A类稍低的一种类型的不合格
C．认为最被关注的一种不合格
D．认为比较被关注的一种不合格
A．Φ(α)-Φ(0)
B．Φ(α-1)/4-Φ(0-1)/4
C．Φ(2-1)/2-Φ(0-1)/2
D．2Φ(0.5)-1
E．Φ(2-1)/2+Φ(1/2)
A．善于确定新的手段或方法
B．为了使任何人都能一目了然，必须把目的或目标的名词或短文以简洁的形式表示出来
C．在为达到目的、目标过程中，如果存在着制约事项，必须予以指明
D．确定目的、目标时，首先要对已经确定的目的、目标，问几个“为什么？”，也就是“为什么要实现该目的、目标？”
E．在确认了更高一级水平的目的、目标之后，还要确认原目的、目标是否恰当
A．抽检方案的检索
B．样本的抽取
C．抽样方案及对批的可接收性的判断
D．转移规则
E．交检批的检验
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