同体积的热水比冷水____，热水会____在冷水上。

    Memory(记忆) is very important. It helps you remember who you are, where you live, what you have learnt and what you plan to do in the future.____ 

    Memory has close relationship with the brain(大脑).____ For example, you can do new things. If you walk a different way to school or take a different bus. You will keep your brain active. You can try to remember something new. You can try to learn new skills.____ Your brain gets lost of regular exercise if you do any of these things.

    If you live a healthy life, your memory will work better. You must have a balanced diet(均衡饮食)not just fast food.____ Unless(如果不)you get enough sleep every night, you will not remember things well.

    ____ If you get too worried, your brain will slow down, and your memory will become less sharp. So, to improve your memory, you should exercise your brain, live a healthy life and stay relaxed.

阅读下面方框中的五个选项（ABCDE），从中选出可以填入空白处的最佳选项，并将其标号填在相应的横线上。

根据短文内容选择正确答案。

    A crow(乌鸦) is about twenty inches (英寸) long and black all over. Crows are dirty birds because they live on bad food. Crows eat a lot of waste food. In this way they are more useful to us than any birds. They clean up the dirty things in our streets. Crows are always hungry. They look for food all day, and in the evening you can see them in large numbers flying back to their nests(巢) in the trees. They sleep there at night.

    Crows are much noisier than other birds. Very often a large number of crows will get together on one house and talk. Sometimes they talk together, and sometimes they do it by turns(轮流) like human beings(人类). It is easy to tell(判断) from crow's sound if they are pleased or angry. Perhaps crows talk a lot because they are friendly birds. A pair of crows will live together all their lives, and if one of them dies, the other one becomes very sad and quiet for the rest of its life and some time later it dies too.

下列说法正确的是（　　）

____