题目

炎热的夏季，小宇同学把装满水的矿泉水瓶放人冰箱冷冻室，当瓶内水完全结冰时拿出后，小宇发现两个现象： （1） 塑料瓶底明显向外凸起； （2） 过了一会儿，原本干燥的瓶外出现了一些细密的小水珠．请你应用所学的物理知识分别解释这两个现象． 答案：答：瓶内的水结冰时，质量不变，由于冰的密度小于水的密度，根据ρ= mV 可知，水结冰后体积变大，所以塑料瓶底向外凸出 答：空气中的水蒸气遇到冰冷的瓶子降温液化成小水珠用括号内所给词的适当形式填空。The picture that sits on my desk in my bedroom is my favourite. When I have difficulty 1. (study) or I'm 2.(worry) about an exam, I always take a look at it. It is a picture of my best friends taken three years ago when we 3. (be) in middle school. It reminds me of the good time we shared and the support they 4. (give) me. Our 5. (life) have been in different directions, but our friendship keeps us close. Every week I 6. (get) a message on my answering machine from one of them or a letter with the 7. (late) news or vacation photos. I often get an email with a joke for the day or words of comfort about some problems in 8. (I) life. My friends never forget my birthday parties, and one of them even travelled two hours from the other end of the town just 9. (watch) my 10. (one) English speech contest. 1.studying 2.worried 3.were 4.gave 5.lives 6.get 7.latest 8.my 9.to watch 10.first 【解析】 本篇文章难度适中，主要讲述我和我的朋友以前的点点滴滴。现在我的朋友虽然不在身边了，但是我们经常联系。 1.句意“每当我在学习上遇到什么困难或者为考试而担...