當前位置：人教版（2019）必修2《Unit 3 The Internet》2020年單元測試卷（二）> 試題詳情

All networks like 3 G and 4 G will be things of the past，because 5 G will be reachable in the near future．So，what's so special about a 5 G future？First of all，its download speed can be as fast as 20 GB/s，which is 100 to 200 times that of 4 G．But what's more impressive is 5 G's low delay rate．Now，4 G takes an average of 200 milliseconds（毫秒） to send and receive information．But 5 G will get it down to 1 millisecond．
   5 G is a great breakthrough．It's going to change the way equipment connects to the Internet，and more importantly，to each other．And self-driving cars may be one of the biggest breakthroughs to come out of 5 G．Human reaction time is 200 milliseconds，yet we still have accidents every day．The self-driving car under a 5 G network could react and communicate its reaction to hundreds of cars around it，all within 1 millisecond．It'll play a great role in preventing car accidents and ending traffic jams completely．
   5 G can benefit us in many other ways．Operations could be performed by robots controlled by experts from the other side of the world．Therefore，more lives will be saved in time．Factories can be staffed by robots that can communicate their tasks to each other，and they can do more work efficiently over a 5 G network．Imagine a group of drones（無人機） flying over a field of crops，using sensors（傳感器） on the ground to sort，pick，feed，and water plants all on their own．Then farmers won't have to work so hard anymore．
   However，5 G is not perfect．One major disadvantage has to do with why it's so fast．5 G uses the millimeter waves，while 4 G uses the 15 to 40 centimeter-long waves．And shorter waves go fast but not very far．On 4 G networks，the signal can go 10 kilometers．But the 5 G signal can go at most 300 meters，and it can't even go through walls or rain．So，what does that mean？Having such a short signal distance means we need to build a lot of transmitters（信號發(fā)射塔） in the future．

（1）How does the author show us 5 G's advantages in Paragraph 1？
B
B

A．By giving examples of the uses of 5 G．
B．By making comparisons between 4 G and 5 G．
C．By explaining the scientific principles of 5 G．
D．By analyzing 5 G's development from 4 G．
（2）According to the author，the self-driving cars will
D
D
．
A．cause more car accidents
B．slow down 5 G's development
C．run without being connected to the Internet
D．have a much faster reaction speed than humans
（3）What does the underlined part "be staffed by robots" in Paragraph 3 mean？
B
B

A．Be built by robots．
B．Have robots as workers．
C．Offer employees home robots．
D．Produce more medical robots．
（4）What does the last paragraph mainly talk about？
A
A

A．The main weakness of 5 G networks．
B．How to make 4 G networks more perfect．
C．The types of long waves and short waves．
D．How to improve the signal of mobile phones．

【考點】說明文．

【答案】B；D；B；A

【解答】

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發(fā)布：2024/4/20 14:35:0組卷：8引用：1難度：0.5

相似題

1．"Snowplow（掃雪機）parenting" is the newest parenting style that can include parents booking their adult children haircuts，calling their college kids to wake them up so that they don't sleep through a test，and even calling their kids' employers.
   "Helicopter （直升機）parenting' means monitoring their kids' every activity，which is out of date. " Claire Cain Miller and Jonah Engel Bromwich wrote in The New York Times. "Some rich mothers and fathers now are more like snowplows：clearing any problems in their children's path to success so that they don't have to meet failure or lose opportunities. "
   There is a mother who started a charity in her son's name to try to raise his chances of being accepted to the college.One set of parents spent years helping their daughter avoid foods with sauce，which she didn't like.Once she got to college，she had problems with the food in her school because it was all covered in sauce.
   A survey says that three-quarters of parents of children between the ages of 18 and 28 ask for doctor visits or haircuts for their children，and 11% say they would call their kids' bosses whether their children are having an issue at work.
   As reported，wealthy parents try to get their children into top colleges by giving a large amount of money to a school，such as paying for a building.This parenting has become the most popular way to raise children，whatever the income，education，or race is.
   Julie，a teacher at Stanford，told the Times that "snowplow parenting" is not a reasonable approach. "The parents should prepare the kid for the road，instead of preparing the road for the kid，" she said.

（1）How does Julie like "snowplow parenting"？

A．It is unreasonable.
B．It is advanced.
C．It is accepted by teachers.
D．It is refused by rich people.
（2）What is the character of "helicopter parenting"？

A．Parents make kids popular.
B．Parents provide little money for kids.
C．Parents ask kids to care for themselves.
D．Parents watch over kids' every activity.
（3）What should parents do according to Julie？

A．Do as wealthy parents do.
B．Make kids be prepared.
C．Make roads be prepared.
D．Do as little as possible.
（4）What's the best title for the text？

A．Helicopter Parenting.
B．The Similarity in Parenting.
C．A Research on Parenting.
D．A New Kind of Parenting.
發(fā)布：2024/11/5 7:30:2組卷：7引用：3難度：0.6
解析
2．American children aren't the only couch potatoes out there.Nearly one third of children in the world spend three hours a day or more watching TV or playing computers，according to a study of over 70，000 teens in 34 nations.
   From Argentina to Zambia，Regina Guthold of the World Health Organization in Geneva and her colleagues found that most children aren't getting enough exercise. "In terms of physical activity levels，we did not find much of a difference between poor and rich countries，" Guthold told Reuters Health. "Growing up in a poor country does not necessarily mean that kids get more physical activity."
   The study，published in The Journal of Pediatrics，looked at 72，845 schoolchildren aged 13 to 15 from Africa，North and South America，Asia，Europe，and the Middle East.
   The researchers defined enough physical activity as at least an hour of exercise outside of gym class at least five days a week.Children who spent three or more hours a day watching TV，playing computer games，or chatting with friends—aside from time in school or time spent doing homework—were considered assedentary .The researchers found only one quarter of the boys and 15 percent of the girls were getting enough exercise bythese definitions .A quarter of the boys and nearly 30 percent of the girls sat too much and didn't get enough exercise.
   Children in Myanmar were the least sedentary，with 13 percent of boys and 8 percent of girls classified as sedentary.
   Girls were less active than boys in every country except for Zambia.Uruguay had the highest percentage of active boys，at 42 percent，while Zambia had the lowest，at 8 percent.Girls from India were the most active，with 37 percent meeting exercise definitions，while girls from Egypt were the least active，with just 4 percent getting enough exercise.
   While the study didn't look at the reasons behind the lack of physical activity in various nations，Guthold guessed that urbanization （城市化） could be a factor as well as being able to use cars and TVs.She said schools can help children become more active by having physical education classes and educating students about the importance of exercise.

（1）What does the underlined word "sedentary" in paragraph 4 mean？

A．Addicted.
B．Flexible.
C．Inactive.
D．Unhealthy.
（2）What can we know from the study？

A．Boys from Uruguay were the most active.
B．Most girls from India got enough exercise.
C．Children in Europe get more physical activity.
D．Boys are more active than girls in every country.
（3）How does the writer present the findings of the study？

A．By using quotations and taking examples.
B．By listing figures and making comparisons.
C．By asking questions and providing answers.
D．By presenting facts and drawing conclusions.
（4）Which of the following factors probably lead to children's lack of physical activity？

A．Computers and potatoes.
B．Computers and urbanization.
C．Urbanization and physical education.
D．Physical education and homework.
發(fā)布：2024/11/1 19:0:1組卷：15引用：4難度：0.5
解析
3．How good are you at maths？Some people love the challenge of algebra（代數(shù)）or enjoy working out number puzzles.Maths is all around us，from working out how to share the bill after a meal，to calculating your family bills.But many are afraid of the moment when they have to deal with numbers and figures and feel a real sense of worry and confusion.It can seem frightening，but this maths anxiety is perfectly normal，and you're definitely not alone.And anyway，our worries and fears don't necessarily reflect our ability.
   The problem really starts in childhood，at school.Research has found that maths teachers who are nervous about teaching the subject can pass on their anxiety to the pupils，and girls may be more likely to be affected.The Programme for International Student Assessment found around 31% of 15—and 16—year—olds across 34 countries said they got very nervous doing maths problems，33% said they got tense doing maths homework，and nearly 60% said they worried that maths classes would be difficult.Shulamit Kahn，a professor from Boston University，believes that giving students，particularly girls，good role models is critical，especially at a young age.She thinks the key is to get people，especially women who love maths，to teach younger children
   Writing for the BBC，David Robson says， "It's not clear why maths causes so much fear compared to geography.But the fact that there's no room for playing tricks might make you more worried about underperforming." And once we assume that we're not a maths person，we avoid solving things that we probably could do.
   Psychologists have been trying to work out why mental arithmetic（心算）can bring us out in a sweat.That seed of fear may come from many sources，but some suggest that voicing your fears can loosen their control over you.They also suggest encouraging children to see a maths test as a challenge，not a threat.Most importantly，we need to think positively about maths and give it a second chance.

（1）What is the author's understanding of maths anxiety in paragraph 1？

A．It happens when you have to pay bills after a meal.
B．It actually reflects one's poor performance in maths.
C．Only students often suffer from this sense of worry.
D．People normally have it when dealing with numbers.
（2）What may cause students' maths anxiety according to the research？

A．The particular feature of maths.
B．The fear of failure in maths tests.
C．Students' dislike of learning maths.
D．Maths teachers' lack of confidence.
（3）What can we infer from David Robson's words？

A．Geography seldom causes worry.
B．Slow students have maths anxiety.
C．Dishonesty is difficult in maths tests.
D．Maths students like number puzzles.
（4）What is the best way to get over maths anxiety？

A．Speaking out your fears in public.
B．Employing female maths teachers.
C．Having a positive attitude to maths.
D．Viewing maths tests as a challenge.
發(fā)布：2024/11/5 0:30:7組卷：24引用：7難度：0.5
解析

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