题目

甲、乙两完全相同的烧杯中装有不同液体，放入两个完全相同的物体，当物体静止后两烧杯中液面恰好相平，如图所示。液体对两个物体下底面的压强分别是 、 ，容器对水平桌面的压力分别是 、 。下列判断正确的是（） A . B . C . D . 答案：DWhen you feel sad, tears will come down from your eyes. When you are happy, especially when you laugh hard, tears will also come down from your eyes. But tears have a more important job than showing your feelings. Tears keep your eyes clean and healthy. They wash away dirt and germs(细菌) just like bath. Your eyes also need tears to keep them wet. And eyes must be wet so that they can move smoothly. Your eyes are busy looking here and there all day long. They move quickly from one thing to another. If you didn’t have tears, your eyes couldn’t move, and soon you would be blind. Maybe you don’t like tears, but your eyes can’t do without them. 1.The story tells us ____. A. what makes people blindB. why people have tearsC. why people cry when they are sadD. what tears are2.Tears help you by ____. A. showing how you feelB. making your face cleanC. washing things from your eyesD. making your eyes bright3.If your eyes were not wet, you could not____. A. look at things clearlyB. laugh and cryC. keep cleanD. show your feelings4.When you are happy or sad, you may ____. A. look at things quicklyB. wash away dirt and germsC. have tears in your eyesD. move your eyes quickly5.The sentence “your eyes can’t do without them” means ____. A. your eyes like having baths very muchB. your eyes like tears very muchC. your eyes can’t work without tearsD. your eyes can’t open without them