题目

如图所示，小梦把装满水的玻璃瓶放在冰箱冷冻室里，过一段时间拿出来发现水结冰后玻璃瓶破裂且外壁有“白霜”，请你解释这两个现象． 答案：【考点】密度公式的应用；生活中的凝华现象． 【分析】（1）质量是指物体所含物质的多少，是物体的一种属性，一个物体位置、状态的改变不会使质量发生变化．一定质量的矿泉水结冰，状态改变、质量不变、密度减小，体积变大； （2）物质由气态直接变为固态叫凝华． 【解答】答： （1）质量是Animals have their special ways to deal with hard times in nature. The superb fairy-wren, one kind of bright-blue bird in Australia, is one example. This year, a ten-year study showed that this small bird has eggs of different sizes in different kinds of weather. When the weather is hot and dry there is less food for young superb fairy-wrens, and they die easily. So the mother bird will make larger eggs to help her babies grow stronger inside before they break out of the eggs into the "hungry" world. However, not all mother birds are able to do this. Only those with at least one male child can. When the weather is "good", the mother will make smaller eggs, and her sons will bring food back for their baby brothers and sisters from the eggs. With her sons' help, the mother can save more energy to make larger eggs when the weather is bad. Isn't this amazing?【1】Which is the best title of the passage?A.The Best Place for Birds.B.The Hard Times in Nature.C.Larger Mother Birds Have Larger Eggs.D.Mother Bird Fights Weather Changes.【2】What does the underlined word "this" mean in the passage?A.Having eggs of different sizes.B.Growing stronger inside the egg.C.Saving food for weaker baby birds.D.Helping baby birds break out of the eggs.【3】What can we learn about superb fairy-wrens from the passage?A.Baby birds grow well in hot, dry weather.B.Male birds can usually live for over ten years.C.Young male birds share the job of feeding the baby birds.D.Mother birds make smaller eggs when there is less food outside.