搜题请搜索小程序“爱下问搜题”
问题 单项选择题

证据是分级的，研究方法对检验因果关系和评价干预效果的论证强度是不同的，由强到弱的顺序是（）

A.队列研究、随机对照试验、病例对照研究、描述性研究、系统综述

B.系统综述、随机对照试验、描述性研究、病例对照研究、队列研究

C.系统综述、随机对照试验、队列研究、病例对照研究、描述性研究

D.随机对照试验、系统综述、队列研究、病例对照研究、描述性研究

答案

参考答案：C

单项选择题

As one works with color in a practical, or experimental way, one is impressed by two apparently unrelated facts. Color as seen is a mobile, changeable thing (1) to a large extent on the relationship of the color (2) other colors (3) simultaneously. It is not (4) in its relation to the direct stimulus which (5) it. On the other hand, the properties of surfaces that give (6) to color do not seem to change greatly under a wide variety of illumination color, usually (but not always) looking much the same in artificial light as in daylight. Both of these effects seem to be (7) in large part to the mechanism of color (8) .

When the eye is (9) to a colored area, there is an immediate readjustment of the (10) of the eye to color in and around the area (11) . This readjustment does not promptly affect the color seen but usually does affect the next area to which the (12) is shifted. The longer the time of viewing, the higher the (13) , and the larger the area, the greater the effect will be (14) its persistence in the (15) viewing situation. As indicated by the work of Wright and Schouten, it appears that, at (16) for a first approximation, full adaptation takes place over (17) time if the adapting source is moderately bright and the eye has been in (18) darkness just previously. Also, (19) of the persistence of the effect if the eye is shifted around from one object to another, all of which are at similar brightness or have similar colors, the adaptation will tend to become (20) over the whole eye.

2（）

A.with

B.between

C.to

D.upon
查看答案
填空题

如果两条直线相交成______，那么这两条直线互相垂直．其中一条直线叫做另一条直线的垂线．互相垂直的两条直线的交点叫做______．
查看答案