问题 单项选择题

在Access的数据库中已建立了“tBook”表,若查找“图书编号”是“112266”和“113388”的记录,应在查询设计视图的准则行中输入( )。

A."112266"and"113388"

B.notin("112266","113388")

C.in("112266","113388")

D.not("112266"and"113388")

答案

参考答案:C

解析: 本题考查查询准则的使用。考生首先要清楚选项中各个运算符的含义,“and”是逻辑运算符,当连接的表达式都为真时,整个表达式为真,否则为假。“not”也是逻辑运算符,当Not连接的表达式为真时,整个表达式为假。“in”是特殊运算符,用于指定一个字段值的列表,列表中的任意一个值都可与查询的字段相匹配。题目要求选出“图书编号”是“112266'’和“113388”的记录,所以选项C正确(当然也可以使用“。r”逻辑运算符来书写准则:“112266”or“113388”)。选项B和选项D都含有逻辑运算符“not”,显示是不对的。

选择题
单项选择题

It is clear that some chemicals can damage the health of animals and humans. (1) , this is not the only problem that (2) be caused by the careless use of chemicals. Chemicals can also (3) the ecological balance of the environment. If the ecological balance is disturbed, the results can be (4) serious.

The (5) of DDT illustrates the problem. DDT, a chemical which kills insects, at first seemed to be a perfect answer (6) many problems. It would control insects that caused dangerous diseases, (7) insects that caused billions of dollars of damage to crops every year. Governments permitted and even (8) the use of DDT. Farmers in many countries (9) to spray it on their crops. The (10) results were good: Damage to crops (11) down, and profits went up. However, the chemical had effects which the scientists didn’t see in (12) . First, it also killed insects which were the (13) enemies of the harmful insects and which were therefore beneficial to farmers. Second, and perhaps worse, DDT did not kill (14) harmful insect. A few insects had natural resistance to the chemical. They (15) and reproduced in large numbers. In a few years there were large numbers of insects which were not (16) by DDT, and there were (17) insects which could act as natural (18) on these new "super-insects". Finally, it became clear that DDT was not solving the insect problem. In fact, it was making the problem worse. It (19) became necessary to find a second (20) for the effects of the first.

11()

A.put 

B.took 

C.broke 

D.went