题干

《初中科学实验活动册》中有一个如图所示的实验:在大试管里装满水,然后把小试管(小试管的直径略小于大试管)放到大试管中,一起倒过来,这时我们观察到水向下流,小试管却向上运动.该实验可以证明(  )

A:大气压的存在

B:牛顿第一定律

C:能的转化与守恒定律

D:物体间力的作用是相互的

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A

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     Becoming Refreshed without sleeping

     Sometimes there is just not enough hours in the day to get everything done and get a good night’s rest.____ Once in a while you can get away with a sleepless night and still feel reasonably good by adjusting your meals and activities.

     ____ The last thing you want to do when you are tired is get warm and cozy, this will cause you to fall asleep. Keeping the air conditioner on will make you feel much more alert and refreshed.

     Eat small amounts. Eating small amounts of healthy food will help refresh you. Fruit and nuts are a good choice because they are nutritious and will energize you ____Try to stick to low carbon meals to keep you going. Chewing gum after your snack or small meal will also help keep you awake.

     Keep it bright. When it is dark your body thinks it is time to go to sleep. Turn on lots of lights, which will trick your body into waking up and feeling better. ____ You get double the benefits if it is daytime.

     Take a break. Taking a little break will help you in the long run. Turn up some energizing music to get yourself positive. Relax and talk to a friend in person or on the phone for a few minutes.____

A. Keep it cool

B. Calm down and sleep

C. Avoid big, heavy meals as they will make you tired

D. Going outside whether it is day or night for some fresh air

E. Missing sleep regularly can make you sick and should be avoided

F. When you are tired, you may just want to sit around and do nothing

G. Having a good time for a few minutes will refresh you quicker than anything else.