the best choice before bed as it is the least fattening. The more fat you take in before bedtime, the greater burden you will put on your body at night.

21.According to the text, the mice fed with daytime milk_______.

A.started sleep more easily

B.were more anxious

C.were less active

D.woke up later

22.Which of the following is true of melatonin according to the text?

A.It's been tested on mice for ten years

B.It can make people more energetic

C.It exists in milk in great amount

D.It's used in sleeping drugs

23.What can be a suitable title for the text?

A.Night Milk and Sleep

B.Fat Sugar and Health

C.An Experiment on Mice

D.Milk Drinking and Health

24.How does the author support the theme of the text?

A.By giving examples.

B.By stating arguments.

C.By explaining statistical data.

D.By providing research results.

　　B

　　If English means endless new words, difficult grammar and sometimes strange pronunciation, you are wrong. Haven't you noticed that you have become smarter since you started to learn a language?

　　According to a new study by a British university, learning a second language can lead to an increase in your brain power.Researchers found that learning other languages changes grey matter.This is the area of the brain which processes information.It is similar to the way that exercise builds muscles.

　　The study also found the younger people learn a second language, the better the effect is.

　　A team led by Dr.Andrea Mechelli, from University College London, took a group of Britons who only spoke English.They were compared with a group of "early bilinguals" who had learnt a second language before the age of five, as well as a number of later learners.

　　Scans showed that grey matter density (密度) in the brain was greater in bilinguals than in people without a second language.But the longer a person waited before mastering a new language, the smaller the difference was.

　　"Our findings suggest that the structure of the brain is changed by the experience of learning a second language," said the scientists.

　　It means that the change itself increases the ability to learn.

Professor Dylan Vaughan Jones of the University of Wales, has researched the link between bilingualism and maths skills."Having two languages gives you two windows on the world and makes the brain more flexible,"he said."You are actually going beyond language and have a better understanding of different ideas."