问题 单项选择题

定位第1条记录上的命令是______。

A.GO TOP

B.GO BOTTOM

C.GO 6

D.SKIP

答案

参考答案:A

解析:[知识点] 表记录的浏览、增加、删除与修改[评析] GO命令直接对记录进行定位,TOP是表头,不使用索引时,记录号为1的记录,使用索引时,索引项排在最前面的索引对应的记录。BOTTOM是表尾,当不使用索引时,是记录号最大的那条记录,使用索引时,是索引项排在最后面的索引项对应的记录。SKIP命令的作用是,当确定了当前记录位置之后,可以用 SKIP命令向前或向后移动若干条记录位置。

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.

20()

A.equivalent

B.uniform

C.contrastive

D.complementary

选择题