焦虑

给定下列四个命题： ①∃x0∈R，sinx0+cosx0＞ 2 ； ②∃x0∈[0， π 2 ]， 1+cos2x0 2 =cosx0； ③已知随机变量X～N（μ，σ2），σ越小，则X集中在μ周围的概率越大； ④用相关指数 n1 =( 3 ，3，3 2 )来刻画回归的效果就越好，R2取值越大，则残差平方和越小，模型拟合的效果就越好．其中为真命题的是______．

选词填空。

romantic     wrong       famous       sleepy      lost

1. Mingming is very ________ in our school and almost every person knows him.
2. Your answer is not right.It's________.
3. I can't find my dictionary.Maybe I________ it.
4. The boy sends a lot of flowers to show his love.It's very ________.
5. I am ________now.I want to go to bed.

现行部颁闸门安装定额工作内容包括（）。

A.闸门埋设件

B.闸门压重物

C.闸门本体

D.闸门附件

E.铸铁

（一） Friends play an important part in our lives, and although we may take the friendship for granted, we often don’t clearly understand how we make friends. While we get on well with a number of people, we are usually friends with only a very few, for example, the average among students is about 6 per person. In all the eases of friendly relationships, two people like one another and enjoy being together, but beyond that, the degree of intimacy between them and the reasons for their shared interest vary enormously. As we get to know people we take into account things like age, race, economic condition, social position, and intelligence. Although these factors are not of prime importance, it is more difficult to get on with people when there is a marked difference in age and background. Some friendly relationships can be kept on argument and discussion, but it is usual for close friends to have similar ideas and beliefs, to have attitudes and interests in common--they often talk about ’ being on the same wavelength’. It generally takes time to reach this point. And the more intimately involved people become, the more they rely on one another. People want to do friends favors and hate to break a promise. Equally, friends have to learn to put up with annoying habits and to tolerate differences of opinion. In contrast with marriage, there are no friendship ceremonies to strengthen the association between two people. But the supporting and understanding of each other that results from shared experiences and emotions does seem to create a powerful bond, which can overcome differences in background, and break down barriers of age, class or race.

Which of the following is not implied in the passage ______

A．Even friends may have differences of opinion.

B．Friends never argue with each other.

C．It generally takes time for people to become close friends.

D．Someone’s habits may annoy his friends.

已知电阻R₁、R₂串联在电路中，则电路的总电阻为（）。

A.R＝R₁＝R₂

B.R＝R₁＋R₂

C.R＝1／R₁＋1／R₂

D.R＝1／R₁＝1／R₂