31. Questions 31 to 35 are based on the following passage.The United States is facing a housing crisis: Affordable housing is inadequate， while luxury homes abound (充裕)， and homelessness remains a persistent problem.Despite this， popular culture and the housing industry market happiness as living with both more space and more amenities (便利设施).Big houses are advertized as a reward for hard work and diligence， turning housing from a basic necessity into a luxury.This is reflected in our homes.The average single-family home built in the United States before 1970 was less than 1，500 square feet in size.By 2016， the average size of a new， single-family home was 2，422 square feet.What’s more， homes built in the 2000s were more likely than earlier models to have more of all types of spaces: bedrooms， bathrooms， living rooms， dining rooms， recreation rooms and garages.There are consequences of living big.As middle-class houses have grown larger， two things have happened.First， large houses take time to maintain， so cleaners and other low-wage service workers are required to keep these houses in order.Second， once-public spaces， where people from diverse backgrounds used to come together， have increasingly become privatized， leading to a reduction in the number of public facilities available to all， and a reduced quality of life for many.Take swimming pools.While in 1950， only 2，500 U.S.families owned pools， by 1999 this number was 4 million.At the same time， public municipal pools were often closed， leaving low-income people nowhere to swim.The trend for bigger housing thus poses ethical questions.Should Americans accept a system in which the middle and upper classes enjoy a luxurious lifestyle， using the low-wage labor of others? Are we willing to accept a system in which an increase in amenities purchased by the affluent means a reduction in amenities for the poor?I believe neither is acceptable.We must change the way we think: living well does not need to mean having more private spaces; instead， it could mean having more public spaces.A better goal than building bigger houses for some is to create more publicly accessible spaces and amenities for all.What are big houses promoted to be in the United States?

36.I make notes in the back of my diary()things to be mended or replaced.

A. 　by

B. 　in

C. 　with

D. 　of

1. Passage NineteenA 3-year-old boy who was lost in the woods for two days is now safe at home.But Casey Hathaway told his rescuers that he was not alone in the rainy， freezing cold woods.He said he was with a friend——a bear.The child went missing on January 22 while playing with friends at his grandmother’s house in the southern state of North Carolina.When the other children returned to the house and Casey did not， the family searched the area for almost an hour before calling the police.Police formed a search and rescue team to look for the young boy in the nearby woods.But two days went by and still——no Casey.The woods of North Carolina are home to many black bears， like this one.It seems one of them helped a little boy while he was lost in the woods.Then on January 24， someone called the police saying they heard a child crying in the woods.Police followed up on the information and found Casey at about 9:30 that night.They pulled him out of some briar (荆棘).He was in good health.Police Officer Chip Hughes said that Casey did not say how he was able to survive in the woods for two days in the cloud， rainy weather， but that “he did say he had a friend in the woods that was a bear that was with him.”Hundreds of people helped in the search and rescue efforts， including some 600 volunteers， federal police and members of the military.Hughes told reporters that at no point did he think Casey had been kidnapped (绑架).Doctors at Carolina East Medical Center treated Casey for minor injuries.He was then released to his family on January 25.According to the passage， Casey’s missing is a case of ().

37. Questions 36 to 40 are based on the following passage.Some people have said aging is more a slide into forgetfulness than a journey towards wisdom.However， a growing body of research suggests that late-in-life learning is possible.In reality， education does an aging brain good.Throughout life， people’s brains constantly renovate themselves.In the late 1960s， British brain scientist Geoffrey Raisman spied growth in damaged brain regions of rats through an electron microscope; their brains were forging new connections.This meant brains may change every time a person learns something new.Of course， that doesn’t mean the brain isn’t affected by the effects of time.Just as height usually declines over the years， so does brain volume: Humans lose about 4 percent every decade starting in their 40s.But that reduction doesn’t necessarily make people think slower; as long as we are alive and functioning， we can alter our brains with new information and experiences.In fact， scientists now suspect accumulating novel experiences， facts， and skills can keep people’s minds more flexible.New pathways can strengthen our ever-changing mental structure， even as the brain shrinks.Conventional fixes like word puzzles and brain-training apps can contribute to mental durability.Even something as simple as taking a different route to the grocery store or going somewhere new on vacation can keep the brain healthy.A desire for new life challenges can further boost brainpower.Research about aging adults who take on new enterprises shows improved function and memory as well as a reduced risk of mental disease.Openness—a characteristic defined by curiosity and a desire for knowledge—may also help folks pass brain tests.Some folks are born with this take-in-the world attitude， but those who aren’t as genetically gifted aren’t necessarily out of luck.While genes can encourage an interest in doing new things， a 2012 study in the journal Psychology and Aging found completing reasoning tasks like puzzles and number games can enhance that desire for novel experiences， which can， in turn， refresh the brain.That’s why brain scientist Richard Kennedy says “It’s not that old dogs can’t learn new tricks.It’s that maybe old dogs don’t realize why they should.”What can we conclude from Geoffrey Raisman’s finding?

A. 　Brain damage seriously hinders one’s learning.

B. 　Brain power weakens slower than we imagine.

C. 　Brains can refresh and improve with learning.

D. 　Brains forge connections under new conditions.

44.Soapy was lucky to escape ()to prison.

A. 　to be sent

B. 　sent

C. 　sending

D. 　being sent

1I.Tony is very disappointed ()the results of the exam.

A. 　with

B. 　for

C. 　toward

D. 　on

3. Passage Thirty-TwoHave you ever heard of a pawpaw (木瓜)? If not， do not feel bad.Many Americans do not know of the fruit， although it is native to the U.S.Once， however， it was one of the most popular fruits in North America.Happily， those who love the pawpaw are trying to return it to its former position in American foods.A pawpaw is a tropical fruit that used to be grown along the East Coast from New York to Florida and all over the eastern U.S.At one time， it could be found as far west as Nebraska.The pawpaw was an important food for Native Americans and even early European settlers.Pawpaws reportedly were a favorite treat of George Washington， the first U.S.president， who especially liked them cold.Thomas Jefferson， the third U.S.president， was also a fan of the fruit.He planted pawpaws at his home in Virginia.He also sent pawpaw seeds to his friends in France.American explorers Lewis and Clark wrote in their journals about the pawpaw.The pawpaw is difficult to be sold commercially.The fruit requires a very special environment—low， wet areas that sometimes flood.It has a very short harvest season， from two to three weeks in September and October.In addition， the fruit is good to eat for only two to three days after harvesting.This makes it hard to sell anywhere distant from the pawpaw tree it comes from.Planters are again growing pawpaw trees and harvesting the fruit.In several states farmers have organized “pawpaw festivals” to reintroduce people to food.At such a festival in Maryland recently， farmers displayed different products made with pawpaws， like pawpaw jams， pies， ice-cream and beer.George Washington and Thomas Jefferson are mentioned in paragraph 3 as ().

3. Passage Thirty-ThreeWe all know that DNA has the ability to identify individuals but， because it is inherited， there are also regions of the DNA strand which can relate an individual to his or her family (immediate and extended)， tribal group and even an entire population.Molecular Genealogy (宗谱学)can use this unique identification provided by the genetic markers to link people together into family trees.Pedigrees (家谱)based on such genetic markers can mean a breakthrough for family trees where information is incomplete or missing due to adoption， illegitimacy or lack of records.There are many communities and populations which have lost precious records due to tragic events such as the fire in the Irish courts during Civil War in 1921 or American slaves for whom many records were never kept in the first place.The main objective of the Molecular Genealogy Research Group is to build a database containing over 100，000 DNA samples from individuals all over the world.These individuals will have provided a pedigree chart of at least four generations and a small blood sample.Once the database has enough samples to represent the world genetic make-up， it will eventually help in solving many issues regarding genealogies that could not be done by relying only on traditional written records.Theoretically， any individual will someday be able to trace his or her family origins through this database.In the meantime， as the database is being created， molecular genealogy can already verify possible or suspected relationships between individuals.“For example， if two men sharing the same last name believe that they are related， but no written record proves this relationship， we can verify this possibility by collecting a sample of DNA from both and looking for common markers (in this case we can look primarily at the Y chromosome (染色体)，” explains Ugo Perego， a member of the BYU Molecular Genealogy research team.The Molecular Genealogy Research Group is building a database for the purpose of ().

3、Now we know that all this is caused by the movement of the earth around the sun.As the earth journeys around the sun， it spins on its own axis.This can be illustrated (解释，说明)by a simple experiment.If you push a sharp stick(尖头棒)through a rubber ball and twirl(使旋转)it with two fingers， the ball spins around in much the same way the earth is spinning at this moment.The points where the stick comes through the ball correspond to(等同于)the North and South Poles.If you twirl this ball at night directly in front of a bright light， you will notice that half of the ball is lighted up while the other half is in the shade(阴暗处).That is just like our night and day.If you keep the stick strictly vertical(垂直的)to the light and twirl it at an even speed， any spot on the ball’s surface will be in the light and in the shade the same length of time.

8.The project ()by the end of 2000， will expand the city＇s telephone network to cover 1，000，000 users.

A. 　accomplished

B. 　being accomplished

C. 　to be accomplished

D. 　having been accomplished

2. Passage Twenty-SevenOut of all the students who enroll in a massive open online course (MOOC)， only about 5 percent complete the course and receive a certificate of accomplishment.This statistic is often cited as evidence that MOOCs are fatally flawed (有缺陷的)and offer little educational value to most students.Yet more than 80 percent of students who fill out a post-course survey say they met their primary objective.How do we look at these two facts? We’re used to focusing on completion rates in higher education， but they’re not the only—or even the most meaningful—indicator of engagement in open online courses.With no cost to enroll， no punishment for dropping out， and little reward for actually earning a certificate， MOOCs are fundamentally different from traditional classes—and students use them in fundamentally different ways.Data from more than 1.8 million students enrolled in 36 MOOCs offered by the University of Pennsylvania show that students treat MOOCs like a buffet (自助餐)， sampling the material according to their interests and career goals.Some are curious about the subject matter and just watch one or two video lectures; others use the discussion forums to connect with their intellectual peers around the world.Of all enrolled students， nearly 60 percent watch at least one video， complete at least one assignment， or post at least once in a forum.So focusing on the tiny fraction of students who complete a MOOC is misguided.The more important number is the 60 percent engagement rate.Students may not finish a MOOC with a certificate of accomplishment， but the courses nonetheless meet the educational goals of millions.In Para.2， the author stresses ().