将命题“凡有理数都能被 2 整除”符号化，下面不合适的为：

>> 成人高等教育 / 离散数学（上）

成人高等教育 / 离散数学（上）

正确率：100%

A、
个体域为有理数集合， $\forall$ xF(x), 其中, F(x): x 能被 2 整除；
B、
个体域为实数集合， $\forall$ x(G(x) $\mapsto$ F(x)), 其中, G(x): x 为有理数, F(x)同上；
C、
个体域为全总个体域， $\forall$ x(G(x) $\wedge$ F(x)), 其中, G(x): x 为有理数, F(x)同上；
D、
个体域为复数域， $\forall$ x(G(x) $\mapsto$ F(x)), 其中, G(x): x 为有理数, F(x)同上；

积分

离散数学（上）

参考答案：

点击查看答案

佳题速递：

常微分方程

This would be a trick playing on him. 大学英语（2）

控制系统抗干扰能力试验中，常用的方法是 ( )。A、现场引入干扰电压法 B、低频干扰法 C、射频干扰法 D、高频干扰法计算机控制系统

演讲稿结尾常见的方法不包括? A、言尽笔止，自然收篇 B、总结全篇，提示主题 C、幽默含蓄，耐人寻味 D、结合现场，联络感情演讲与口才

题型描述: 阅读理解In the United States, it is not customary to telephone someone very early in the morning． If you telephone him early in the day, while he is shaving or having breakfast, the time of the call shows that the matter is very important and requires immediate attention． The same meaning is attached to telephone calls made after 11:00pm． If someone reeives a call during sleeping hours, he assumes itˊs a matter of life or death． The time chosen for the call communicates its importance． In social life, time plays a very important part． In the U. S. A． guests tend to feel they are not highly regarded if the invitation to a dinner party is extended only three or four days before the party date． But it is not true in all countries． In other areas of the world, it may be considered foolish to make an appointment too far in ad-vance because plans which are made for a date more than a week away tend to be forgotten． The meaning of time differs in different parts of the world． Thus, misunderstandings arise between people from different cultures that treat time differently． Promptness is valued high-ly in American life, for example． If people are not prompt, they may be regarded as impolite or not fully responsible． In the U. S. no one would think of keeping a business associate waiting for an hour, it would be too impolite． A person who is 5 minutes late, will say a few words of explanation, though perhaps he will not complete the sentence．1、 What is the main idea of this passage? A. It is not customary to telephone someone in the morning and in sleeping hours in the U．S． B. The role of time in social life over the world． C. Not every country treats the concept of time as the same． D. If people are not prompt, they may be regarded as impolite or not fully responsible in the U．S． 2、 What does it mean in the passage if you call someone during his or her sleeping hours? A. A matter of life or death． B. A matter of work． C. You want to make an appointment with him or her． D. You want to see him or her． 3、 Which of the following time is proper if you want to make an appointment with your friend? A. at 4:00 am． B. at 4:00 pm． C. at the midnight． D. at 7:00 am． 4、 Which of the following statements is true according to the passage? A. Promptness is valued highly in American life． B. There is no misunderstanding arising between people from different cultures about the concept of time． C. It may be considered foolish to make an appointment well in advance in the U.S.A．． D. In the U．S．A． guests tend to feel they are highly regarded if the invitation to a dinner party is extended only three or four days before the party date． 5、 From the passage we can safely infer that ． A. if a person is late for a date, he neednˊt make some explanation B. itˊs a matter of life or death if you call someone in day time C. it makes no difference in the U.S. whether you are early or late for a business party D. the meaning of time differs in different parts of the world统考英语A

本课说明，数学在电子学中的作用医用电子学