《赤壁赋》中云：“盖将自其变者而观之，则天地曾不能一瞬；自其不变者而观之，则物与我皆无尽也”。这一观点与下列思想对应基本一致的是（   ）

① $f\left(x+\frac{\pi }{4}\right)$ 为偶函数；

②函数f（x）的图象关于点 $\left(\frac{7\pi }{4}，0\right)$ 对称；

③ $f\left(-\frac{3\pi }{4}\right)$ 是函数f（x）的最小值；

④记函数f（x）的图象在y右侧与直线 $y=\frac{m}{2}$ 的交点按横坐标从小到大依次记为P₁，P₂，P₃，P₄，…，则|P₂P₄|=π；

⑤ $\frac{n}{m}=1$ ．

其中真命题的有几个？____（写出所有正确命题的序号）

完形填空
   Monday morning is an important time at our school. All of the students go to the playground.
   We listen to music, and we  1 the national flag(国旗) go up.
   Usually, one student gives a talk on Monday mornings. One Monday last year, a boy gave the talk. He was  2 and excited ! When I saw him, I wanted to have a try, too. Can I really do it?
   Last week, our teacher said our class should give the talk. My teacher 3me, "I know you want to have a try. Next Monday, you can give the talk. Go and write something down. Get ready for it, I'm sure you'll do well." "Thank you ," I answered, It was such a great  4 for me ! When I got home , I was excited. I wrote two pages for the talk. I read them again and again. When I read, I asked my parents  5  . I wanted to make my teacher happy.
   Monday morning came. I began to feel  6 When did I last give a talk to so many people ? Never! This was my first time. Could I really do it?  Maybe I couldn't finish the talk.
   When I got to school, we all went out to playground. I  7  in front of everyone. I opened my mouth, but I couldn't say anything. "Take it easy," I said to 8 . " Don't be nervous. You can do it."
   Just then, I looked down at everyone. I saw about 1,000 eyes. They were all looking at me ! I couldn't even stand up. I looked at their eyes more carefully. Their eyes were saying , "You can do it! Don't be afraid, just talk !" I  9a big breath(呼吸). Then I began to talk. It wasn't hard. It was easy. I don't know  10 I finished my talk. But I did it. I felt so good that day. I showed myself
to everyone what I can do.

    The meaning of silence varies among cultural groups. Silences may be thoughtful, or they may be empty when a person has nothing to say. A silence in a conversation may also show stubbornness, uneasiness, or worry. Silence may be viewed by some cultural groups as extremely uncomfortable; therefore attempts may be made to fill every gap (间隙) with conversation. Persons in other cultural groups value silence and view it as necessary for understanding a person's needs.

    Many Native Americans value silence and feel it is a basic part of communicating among people, just as some traditional Chinese and Thai persons do. Therefore, when a person from one of these cultures is speaking and suddenly stops, what maybe implied (暗示) is that the person wants the listener to consider what has been said before continuing. In these cultures, silence is a call for reflection.

    Other cultures may use silence in other ways, particularly when dealing with conflicts (冲突) among people or in relationships of people with different amounts of power. For example, Russian, French, and Spanish persons may use silence to show agreement between parties about the topic under discussion. However, Mexicans may use silence when instructions arc given by a person in authority rather than be rude to that person by arguing with him or her. In still another use, persons in Asian cultures may view silence as a sign of respect, particularly to an elder or a person in authority.

    Nurses and other care-givers need to be aware of the possible meanings of silence when they come across the personal anxiety their patients may be experiencing. Nurses should recognize their own personal and cultural construction of silence so that a patient's silence is not interrupted too early or allowed to go on unnecessarily. A nurse who understands the healing (治愈) value of silence can use this understanding to help in the care of patients from their own and from other cultures.