选择最佳应答语（  ）

把﹣m$\sqrt{-\frac{1}{m}}$根号外的因式移到根号内，则得____ ．

细胞核分裂时，（　　）的变化最明显．

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

        Amy, a student in the USA, says that the best diet is to reduce what you eat and doplenty of exercise. Get involved in extra activities and never eat after 9 pmin case what you have eaten turns fat because your body system slows down inthe evening and also while you sleep.____ 

Davidis studying in the USA and he believes that it is a good idea to increase the fiber he eats. ____  Fresh is the best: beans and special fiber materials are excellent choices.

        In the UK, students believe that life as a student can be very difficult. ____ One student, Jennifer, believes that you should eat well, rest well, takevitamins to supplement your diet and you will stay healthy.

        But why are so many young people obsessed with diet and exercise? Mostly because they realize they are putting on weight and they know that obesity can lead toillnesses such as diabetes. Why do they put on weight? ____  They get uplate in the morning, dress quickly, eat quickly and then at lunch they often eat fast food and drink soda, both of which are fattening. They then sit chatting to friends, go back to class and sit listening, and late in the afternoon they leave school, meet friends and sit and chat again. If you arelike most kids, you might have the same experience.

      So,are you a student who is putting on weight? Which of the advice from other students do you think you will act on? ____  So, think about your health and weight. They are both very important for your well－being and your marks at school.

A．Because they lead an unhealthylifestyle and eat the wrong foods.

B．A healthy body means both a healthymind and better marks at school.

C．That means for one whole day they haveeaten fattening foods without exercise.

D．This is found in whole grains, fruitand vegetables which are common and daily foods.

E．Try to go for at least a 10－minute walk after eating, or betterstill, go for a jog or a bicycle ride.

F．You study hard, find yourself understress and then spend a long time out with friends relaxing.

G．Because students who don't exercisetend to put on weight sooner and see a drop in their test scores.