题目内容：

We all think best when we're well rested． A clear， alert brain allows us to focus， learn and remember information， and to be creative． On the other hand， when we're sleepy， we make more mistakes and are less productive in school and at work． In a report from Psychological Science， researchers at the University of Paris report sleeping between two learning sessions improve your learning．

In this study， 60 French adults were randomly divided into a "sleep" or "wake" group． They all were given 16 French-Swahili words in pairs in random order． After studying a pair for seven seconds ， the Swahili word appeared on a screen and the participants were asked to type the French translation． If they made a mistake， the words appeared again until every word-pair was correctly translated． Twelve hours later， they did it again． The wake group did their tests first in the morning and then in the evening so they had no time to sleep in between． The sleep group members did their first session in the evening and the second came the next morning， after a good night's sleep．

The sleep group members did much better at recalling the correct translations and were quicker to learn when they make a mistake． Both groups were eventually able to learn all the word-pairs but getting some sleep allowed the sleep group to learn in less time and with less effort， A follow-up showed that the sleep group still did better than the wake group a week later and even six months later，

So， if you have to learn something， study and then get a good night's sleep．

1.What is the difference of the two groups' tasks？ ______

A. Who to learn．    B. What to learn．

C. How to learn the words．    D. When to learn the words．

2.How did the participants deal with a typing mistake they made？ ______

A. Translating the same word again．

B. Leaving the wrong word alone．

C. Asking for a correct answer．

D. Redoing the typing twelve hours later．

3.What does the underlined word it in Para． 2 refer to？ ______

A. Correcting the mistakes．

B. Typing the French translation．

C. Typing the Swahili words．

D. Showing the Swahili word on the screen．

4.Compared to the wake group ， those in the sleep group ______ ．

A. typed more quickly

B. made fewer translation mistakes．

C. learned with more effort．

D. learned all the word- pairs．