下列有关mRNA的特点，哪项是错误的（） A.代谢活跃 B.分子大小不一 C.其5’

We often act like babies when we want to be happy. Why? I think it is because children have no worry and they don’t complain.

We can set a goal in our life and go after what we want. But if we’re  ①   all the time, how can we live happily? If you don’t believe me, count how many ①   you complain about something in one day. Whether it is being trapped in busy traffic or troubled by weather, or whatever it is, there are endless things you can find to complain about.

But it’s not just the outside condition that we will complain about. We complain about ourselves too. We complain that we don’t have enough time or money, and that we’re not smart enough, cool enough, or just enough. Many times we experience lots of unpleasant things because of complaining about things we can’t control.

Think about how much happier you would be if you stopped complaining? ②Much of what you complain about is out of your control anyway. What’s the meaning of thinking about something you have no power to change?

Finding out what you are complaining about is the first step to stop complaining. Ask yourself if you prefer to complain or to be happy.

It’s best to stop to enjoy the beautiful life, but not to waste time to complain.

小题1:在①处填上适当的词，使文章完整。                    

小题2:将②译成中文。

小题3:在文中找出下列句子的同义词：We can have a life goal and try to get it.

小题4:根据短文回答问题：

What should you do first to stop complaining?

小题5:找出文章的中心句。

在常温常压下，a，b，c，d四支相同的试管中，分别装入以等物质的量混合的两种气体。a试管内是NO₂和O₂,b试管内是C1₂和SO₂，c试管内是NO和O₂，d试管内是O₂和H₂。将四支试管迅速同时倒立于水中，最终水面上升高度h的比较，正确的是

A．h_b＞h_c＞h_a＞h_d

B．h_c＞h_a＞h_b＞h_d

C．h_d＞h_a＞h_c＞vh_b

D．h_b＞h_a＞h_c＞h_d

随着人们生活水平的提高．轿车已逐步进入我国普通百姓家中。已知某国产骄车每行驶100km消耗8L汽油(1L＝10^-3 m³)，汽油的密度为0.71×10³kg/m³、热值为4.6×10⁷J／kg。则

（1）10kg汽油完全燃烧时所产生的热量是_________J．

（2）该汽车行驶100km消耗的汽油的质量是________kg．

（3）当该汽车以50kW的功率在平直公路上以72km／h的速度匀速行驶时，它所受到的阻力等于____N。

压力管道在投用前，对管道的强度和材料的紧密性进行压力试验，真空操作的压力管道，其试验压力为（）MPa。

A、0.5

B、1

C、0.2

D、3

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