Being able to multitask-- doing several things at the same time is considered a welcome skill by most people. But if we consider the situation of the young people    1    from eight to eighteen, we should think again.

What we often see nowadays is that young people juggle (玩）an ever larger number of     2     devices as they study. While working, they also surf on the Internet, send out emails, answer the telephone and listen to music on their ipads. In a sense, they spend a     3     amount of time in fruitless efforts as they multitask.

Multitasking is even changing the     4     between family members. As young people pay so much attention to their own worlds, they seem to have no time to spend with the other people around them. They can no longer     5     family members when they enter the house, nor can they eat at the family table.

Multitasking also affects young people's    6     at university and in the workplace. When asked about their opinion of the effect of modern gadgets(器具)on their performance of tasks, many young people gave a     7     response. However, the response from the worlds of education and business was not quite as positive. Educators feel that multitasking by children has a serious effect on later development of study skills. They believe that many college students now need help to     8     their study skills;     9    , employers feel that young people entering the job market need to be taught all over again, as modern gadgets have made it unnecessary for them to learn special skills to do their work.

3 . Nothing seems more inevitable than aging and death ---- not even taxes. Every plant, animal and person you have ever seen will _________ die. But some recent research suggests that aging as we know it may not be inevitable. Indeed, as our _________ of it grows, aging can be viewed not as an unchangeable reality from which there is no escape, but as the product of biological processes that we may be able to _________ someday.

We already know that some animals do not seem to age. Many cold-water ocean fish and some amphibians (两栖动物) never _________ a fixed size; they continue to grow bigger, to be able to reproduce and to live until something kills them. What these _________ seem to be telling us is that something in their genes ---- and possibly in ours ---- controls the _________ of aging, and that aging is not the fate of every living thing.

_________ the history of life on earth, one of the most common difficulties that animals (and their cells) have faced has been a lack of food. About 70 years ago, scientists discovered that when animals are forced to live on 30 to 40 percent fewer calories than they would _________ eat, something unusual happens: they become _________ to most age-related diseases ---- cancer, heart disease, diabetes (糖尿病) ---- and live 30 to 50 percent longer. Restricting calories __________ aging. But what are the __________ genes that preserve vitality( 生命力 ) and starve off（抑制） diseases?

About 15 years ago, armed with powerful new molecular-research techniques, a few scientists began to __________ these genetic phenomena. They have discovered that a gene called Sir2 ---- which is present in all animals, including humans ---- is __________ for the health benefits of calorie restriction, perhaps by repairing our DNA. But if we had to restrict our calorie intake by 30 to 40 percent, would it be of any __________ use? Few of us would be capable of restricting our diets so severely that we were constantly __________ : whether or not it made life longer, it would surely make life feel longer.