Power Napping is Good for the I.Q.

    Today we hear more and more about the importance of getting enough sleep—about eight hours a night. Sleep can help heal and give energy to both the body and the brain. ____1____ It seems almost certain that the third of our lives that we spend asleep has a great effect on the two-thirds that we are awake. Sleep affects our emotions, memory, focus, and behavior.

    Studies show that people in developed countries spend less time asleep and more time at work or commuting. Dr. Karine Spiegel, at the UniversityofChicago, has found that the average length of sleep has gone down from nine hours a night in 1910 to seven-and-a-half hours a night today. However, our bodies cannot function well without enough sleep. ____2____ According to Canadian scientist Dr. Stanley Coren, every hour of lost sleep at night causes us to lose one I.Q. point the next day. For example, when someone gets only five or six hours of sleep each night for a week, the person’s I.Q. could go down 15 points or more. ____3____

    Most sleep experts say that humans need at least eight hours of sleep every day, but it should be in two stages: a long sleep at night and a shorter nap in the afternoon. Some companies help their employees follow this advice. ____4____ They say this makes the workers much more efficient.

    To study sleep deprivation (not getting enough sleep), scientists use a test called the Multiple Sleep Latency Test (MSLT). During the test, a person stays in a darkened, quiet room during the daytime. Scientists believe that a sleep-deprived person will fall asleep quickly. If it takes ten minutes or longer to fall asleep, the person is probably getting enough sleep.

    Scientists have also found that the time of year seems to affect how much sleep we need. ____5____ However, in the summer, people sometimes sleep as little as six hours, without having any problems.

词汇：

emotion [bɪ"ri:vmənt] n. 情绪

commuting [kə"mju:t] n. 乘公交车上下班，通勤

I.Q. n. 智商（全称为intelligent quotient）

deprivation [kə"mju:t] n. 剥夺，匮乏

Sleep Latency Test n. 睡眠潜伏期

注释：

1．have/has an effect on... 对……有效果的

2．go down from... to...从………降至……

练习：

A　They allow them to “power nap” in the afternoon, if only for 20 minutes.

B　Losing just one or two hours of sleep a night, over a long period of time, can cause serious health problems.

C　People usually sleep longer in the winter, sometimes as much as 14 hours a night.

D　People in power are more intelligent because they take naps.

E　Medical experts now believe that sleep is even more important for health than diet or exercise.

空3

A:A B:B C:C D:D E:E F:F

The Value of Motherhood

    In shopping malls, the assistants try to push you into buying "a gift to thank her for her unselfish love". When you log onto¹ a website, a small pop-up² invites you to book a bouquet for her. Commercial warmth and gratitude are the atmosphere being spread around for this special Sunday in May.

     ____1____The popularity of Mother"s Day around the world suggests that Jarvis got all she wanted. In fact, she got more一enough to make her horrified.

    ____2____They buy, among other things, 132 million cards. Mother"s Day is the No 1 holiday for flower purchases. Then there are the various commodities, ranging from jewelry and clothes to cosmetics and washing powder, that take advantage of the promotion opportunities. Because of this, Jarvis spent the last 40 years of her life trying to stop Mother"s Day. One protest against the commercialization of Mother"s Day even got her arrested-for disturbing the peace, interestingly.

    ____3____As Ralph Fevre, a reporter at the UKnewspaper The Guardian, observe, traditionally "motherhood is something that we do because we think it"s right." But in the logic of commercialism, people need something in exchange for their time and energy. A career serves this purpose better.

    ____4____So they work hard and play hard. Becoming a mother, however, inevitably handicaps career anticipation. 

    ____5____According to The Guardian, there are twice as many child-free young women as there were a generation ago. Or, they put off the responsibility of parenting until later in their lives.

    So, Fevre writes that the meaning of celebrating Mother"s Day needs to be updated: "It is to persuade people that parenting is a good idea and to honor people for their attempt to be good people."

词汇：

motherhood /"mʌðəhud/ n．母性

bouquet/ "bʊkeɪ / n．花束

website /"websait/n．网站

注释：

1．log onto：登录到。log onto a website：登录到一个网站

2．pop-up：弹出式菜单

…a small pop-up invites you to book a bouquet for her一张小的弹出式菜单要你为她订一束花。

练习：

A　The American version of Mother"s Day was thought up as early as 1905, by Anna Jarvis, as a way of recognizing the real value of motherhood.

B　But what"s more, commercialism changes young people"s attitude towards motherhood.

C　Obviously, the best gift will be a phone call or a visit.

D　According to a research by the US card company Hallmark,96 percent of American consumerscelebrate the holiday.

E　As a result, motherhood has suffered a huge drop in status since the 1950s.

F　In addition, women are being encouraged to pursue any career they desire.

空3

A:A B:B C:C D:D E:E F:F

Across the Deserts

　　The SaharaDesertis the largest desert in the world. It stretches across Africa fromSenegaltoEgypt. TheSaharaDesertis an unfriendly environment. During the day it"s very hot, and at night it’s sometimes very cold. It is also difficult to find water in theSahara.

　　In 2006, Kevin Lin, Ray Zahab, and Charlie Engle decided to do something very difficult. They made the decision to run across the Sahara Desert 4,300 miles (6,920km). It seemed impossible to do, but they wanted to try. The three men liked to test themselves, and this would be a very big test.

　　On the morning of November 2, Kevin, Ray, and Charlie started their trip across theSahara. Every morning they began running at 5:00. At11 a.m. they stopped and rested until 5 p.m. Then they ran again until 9:30 in the evening. Each day they ran about 40 miles (64 km). Every day it was the same thing. They got up and ran. They listened to music on their iPods, and they ran and ran.

　　Kevin, Ray, and Charlie needed to eat a lot of food during their trip. Most people need about 2,000 calories of food each day. Kevin, Ray, and Charlie needed between 6,000 and 9,000 calories every day. That"s a lot of food! They also needed to drink a lot of water.

　　The three men had some problems on their trip, and many times they wanted to quit and go home. It was often very hot (140°F/60°C) during the day, and the heat made them sick. Their legs and feet hurt. Sometimes it was very windy, and they couldn"t see. One time they got lost. But they didn"t quit. After 111 days, Kevin, Ray; and Charlie successfully finished their trip across theSaharaDesert. They hugged each other and put their hands in the water of theRed Sea. Then they ran to a hotel to take a long shower.

　　词汇：

　　Stretch / strɛtʃ / v. 延伸，伸展

　　Calorie / "kælərɪ / n. 卡(路里)，小卡，大卡

　　Quit / kwɪt / v. 停止，放

　　注释：

Each day the men ran for approximately eight hours.

A:Right B:Wrong C:mentioned

Across the Deserts

　　The SaharaDesertis the largest desert in the world. It stretches across Africa fromSenegaltoEgypt. TheSaharaDesertis an unfriendly environment. During the day it"s very hot, and at night it’s sometimes very cold. It is also difficult to find water in theSahara.

　　In 2006, Kevin Lin, Ray Zahab, and Charlie Engle decided to do something very difficult. They made the decision to run across the Sahara Desert 4,300 miles (6,920km). It seemed impossible to do, but they wanted to try. The three men liked to test themselves, and this would be a very big test.

　　On the morning of November 2, Kevin, Ray, and Charlie started their trip across theSahara. Every morning they began running at 5:00. At11 a.m. they stopped and rested until 5 p.m. Then they ran again until 9:30 in the evening. Each day they ran about 40 miles (64 km). Every day it was the same thing. They got up and ran. They listened to music on their iPods, and they ran and ran.

　　Kevin, Ray, and Charlie needed to eat a lot of food during their trip. Most people need about 2,000 calories of food each day. Kevin, Ray, and Charlie needed between 6,000 and 9,000 calories every day. That"s a lot of food! They also needed to drink a lot of water.

　　The three men had some problems on their trip, and many times they wanted to quit and go home. It was often very hot (140°F/60°C) during the day, and the heat made them sick. Their legs and feet hurt. Sometimes it was very windy, and they couldn"t see. One time they got lost. But they didn"t quit. After 111 days, Kevin, Ray; and Charlie successfully finished their trip across theSaharaDesert. They hugged each other and put their hands in the water of theRed Sea. Then they ran to a hotel to take a long shower.

　　词汇：

　　Stretch / strɛtʃ / v. 延伸，伸展

　　Calorie / "kælərɪ / n. 卡(路里)，小卡，大卡

　　Quit / kwɪt / v. 停止，放

　　注释：

In the middle of the day: the men usually stopped running.

A:Right B:Wrong C:mentioned

Across the Deserts

　　The SaharaDesertis the largest desert in the world. It stretches across Africa fromSenegaltoEgypt. TheSaharaDesertis an unfriendly environment. During the day it"s very hot, and at night it’s sometimes very cold. It is also difficult to find water in theSahara.

　　In 2006, Kevin Lin, Ray Zahab, and Charlie Engle decided to do something very difficult. They made the decision to run across the Sahara Desert 4,300 miles (6,920km). It seemed impossible to do, but they wanted to try. The three men liked to test themselves, and this would be a very big test.

　　On the morning of November 2, Kevin, Ray, and Charlie started their trip across theSahara. Every morning they began running at 5:00. At11 a.m. they stopped and rested until 5 p.m. Then they ran again until 9:30 in the evening. Each day they ran about 40 miles (64 km). Every day it was the same thing. They got up and ran. They listened to music on their iPods, and they ran and ran.

　　Kevin, Ray, and Charlie needed to eat a lot of food during their trip. Most people need about 2,000 calories of food each day. Kevin, Ray, and Charlie needed between 6,000 and 9,000 calories every day. That"s a lot of food! They also needed to drink a lot of water.

　　The three men had some problems on their trip, and many times they wanted to quit and go home. It was often very hot (140°F/60°C) during the day, and the heat made them sick. Their legs and feet hurt. Sometimes it was very windy, and they couldn"t see. One time they got lost. But they didn"t quit. After 111 days, Kevin, Ray; and Charlie successfully finished their trip across theSaharaDesert. They hugged each other and put their hands in the water of theRed Sea. Then they ran to a hotel to take a long shower.

　　词汇：

　　Stretch / strɛtʃ / v. 延伸，伸展

　　Calorie / "kælərɪ / n. 卡(路里)，小卡，大卡

　　Quit / kwɪt / v. 停止，放

　　注释：

They sometimes felt sick because it was so hot.

A:Right B:Wrong C:mentioned

Across the Deserts

　　The SaharaDesertis the largest desert in the world. It stretches across Africa fromSenegaltoEgypt. TheSaharaDesertis an unfriendly environment. During the day it"s very hot, and at night it’s sometimes very cold. It is also difficult to find water in theSahara.

　　In 2006, Kevin Lin, Ray Zahab, and Charlie Engle decided to do something very difficult. They made the decision to run across the Sahara Desert 4,300 miles (6,920km). It seemed impossible to do, but they wanted to try. The three men liked to test themselves, and this would be a very big test.

　　On the morning of November 2, Kevin, Ray, and Charlie started their trip across theSahara. Every morning they began running at 5:00. At11 a.m. they stopped and rested until 5 p.m. Then they ran again until 9:30 in the evening. Each day they ran about 40 miles (64 km). Every day it was the same thing. They got up and ran. They listened to music on their iPods, and they ran and ran.

　　Kevin, Ray, and Charlie needed to eat a lot of food during their trip. Most people need about 2,000 calories of food each day. Kevin, Ray, and Charlie needed between 6,000 and 9,000 calories every day. That"s a lot of food! They also needed to drink a lot of water.

　　The three men had some problems on their trip, and many times they wanted to quit and go home. It was often very hot (140°F/60°C) during the day, and the heat made them sick. Their legs and feet hurt. Sometimes it was very windy, and they couldn"t see. One time they got lost. But they didn"t quit. After 111 days, Kevin, Ray; and Charlie successfully finished their trip across theSaharaDesert. They hugged each other and put their hands in the water of theRed Sea. Then they ran to a hotel to take a long shower.

　　词汇：

　　Stretch / strɛtʃ / v. 延伸，伸展

　　Calorie / "kælərɪ / n. 卡(路里)，小卡，大卡

　　Quit / kwɪt / v. 停止，放

　　注释：

On their trip across the desert: the three men ran through five countries.

A:Right B:Wrong C:mentioned

假设5个进程P0、P1、P2、P3、P4共享三类资源R1、R2、R3，这些资源总数分别为18、6、22。T0时刻的资源分配情况如表模拟2.1所示，此时存在的一个安全序列是( )。 表模拟2.1　T0时刻资源分配情况
进程 已分配资源 资源最大需求 R1 R2 R3 R1 R2 R3 P0 3 2 3 5 5 10 P1 4 0 3 5 3 6 P2 4 0 5 4 0 11 P3 2 0 4 4 2 5 P4 3 1 4 4 2 4

A:P0, P2, P4, P1, P3 B:P1, P0, P3, P4, P2 C:P2, P1, P0, P3, P4 D:P3, P4, P2, P1, P0

假设5个进程P0、P1、P2、P3、P4共享三类资源R1、R2、R3，这些资源总数分别为18、6、22。T0时刻的资源分配情况如下表所示，此时存在的一个安全序列是 进程 已分配资源 资源最大需求 R1 R2 R3 R1 R2 R3 P0 3 2 3 5 5 10 P1 4 0 3 5 3 6 P2 4 0 5 4 0 11 P3 2 0 4 4 2 5 P4 3 1 4 4 2 4

A:P0，P2，P4，P1，P3 B:P1，P0，P3，P4，P2 C:P2，P1，P0，P3，P4 D:P3，P4，P2，P1，P0

假定系统中有五个进程P0、P1、P3、P3、P4和三种类型的资源A、B、C，系统中每一种资源的数量分别为10、5、7，在T0时刻的资源分配情况如表6-19所示。 P0发出请求向量Request0=(0，2，0)，系统按银行家算法进行检查： Request0=(0，2，0)≤Needo(7，4，3) Request00=(0，2，0)≤Available=(3，3，2) 于是，系统先假定可为P0分配资源，如果进程按（）列执行，那么系统状态是安全的。

A:P₀、P₁、P₂、P₃、P₄ B:P₁、P₂、P₀、P₃、P₄ C:P₃、P₁、P₂、P₀、P₄ D:P₃、P₁、P₀、P₂、P₄

设系统中有三种类型的资源(A、B、C)和五个进程(P0，P1，P2，P3，P4)，某时刻的状态如下：
根据银行家算法可知，该时刻存在着一个安全序列______。

A:P1,P3,P0,P4,P2 B:P2,P4,P1,P3,P0 C:P4,P1,P0,P3,P2 D:P3,P1,P2,P4,P0