2021高考英语一轮复习课时作业21Unit21HumanBiology北师大版选修7

课时作业21 Unit 21 Human Biology

课时练(一) 阅读理解·组块专练——练速度

(限时：35分钟)

阅读理解(共两节，满分40分)

第一节 (共15小题；每小题2分，满分30分)

阅读下面短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。

A

[2020·湖北省高考模拟]With its snow-covered mountains and a variety of wildlife, Yellowstone National Park is one of the scenic treasures of the United States. Located primarily in Wyoming, the park hosts millions of visitors every year. If you plan to travel within the park, keep in mind the advice from the National Park Service.

Seasonal Travel

Travel varies vastly from season to season. Roads are generally open in the summer except for cases of rock or mud slides, wild fires, accidents or road construction. Early snows in the fall can cause some roads to close temporarily. In the winter almost all roads are closed to motor vehicles, but snowmobiles and other snow vehicles with tracks are allowed. Roads begin to open in the spring by the latter part of April but may close if snowfall continues.

Driving Time

Grand Loop Road is the main road through Yellowstone National Park, and it passes by most of the major attractions. These include Old Faithful, Yellowstone Lake and the Grand Canyon of Yellowstone. The maximum speed limit on the Grand Loop is 45 miles per hour, but the speed limit drops during some of the winding and twisty sections of this narrow road. Allow yourself at least two days to fully travel the loop due to the size of the park and occasionally heavy traffic.

Safety Awareness

Buffalo often block the roads in the park as they migrate through the fields. If a herd is traveling across the road you are on, you can either wait for them to pass or find an alternative route. If you get out of your vehicle, you should stay at least 25 yards from any buffalo (and 100 yards or more away from bears and wolves). Buffalo are particularly unpredictable and charge people at speeds up to 30 mph.

You can take your bicycle on any public roads and routes designed for bikes, but bicycles are not allowed on the park roads which are narrow with few shoulders. Elevations range from 5,300 to 8,860 feet. The National Park Service recommends that cyclists wear helmets and noticeable clothing.

1．What is TRUE about traveling in the Yellowstone Park? A．Roads will stay open in spite of emergency. B．Traffic jam is actually a rare thing. C．The driving speed on the road can be 50 mph. D．Motor vehicles are allowed in the winter.

2．What safety advice does the National Park Service offer? A．Under no circumstances could you get out of the car. B．Keep going forward when coming across the buffalo. C．Do wear easy-to-see clothes while bicycling. D．Bicycling is forbidden on the public roads. 3．Where can you probably find this article? A．In a guidebook.

B．In a geography textbook. C．In a research paper.

D．In a commercial advertisement.

B

[2020·昆明市教学质量检测]Five-year-old Prisilla Perez, a student at Meador Elementary School in Willis, was unhappy with her recent haircut, which resulted from a severe disease. When students in her class started calling Prisilla a boy, she felt ashamed, often crying and losing focus in school.

Her teacher, Shannon Grimm, sympathized with her unhappiness. Grimm and Prisilla's mom were concerned, but their ideas didn't work.“We had classroom discussions about how girls have short hair and boys have long hair, and I showed them photos of movie stars with different looks，” Grimm said. “However, it wasn't sinking in.”

Grimm thought about Prisilla throughout the winter break, and one morning, she had an idea: Cut off her hair — a scary thought for Grimm, who wore her hair long and took pride in it.“I've never had short hair, and I stressed about it for two weeks before making a decision，” she said. On Jan. 4, Grimm invited a hairstylist friend to her home. “I told him to keep going, even if I cried，” she said.

The class loved their teacher's new do, especially Prisilla, who excitedly ran off the school bus that afternoon yelling，“Mom, Ms. Grimm cut her hair！” The teacher also bought matching bows for herself and the girl, so they could style their hair together.

In February, the teacher recommended Prisilla for the school district's Student of the Month Award, but during the Monday ceremony, she received a surprise“hero medal” from the girl. “Now we have matching awards，” says Grimm.

Prisilla's mother, Maria, said that Grimm's thoughtfulness brought her to tears.“I was shocked. I was crying. I couldn't believe it — she did something I wouldn't have the bravery to do. I will never forget that.”

4．Why was Prisilla unhappy at school? A．She wasn't satisfied with her teacher. B．She couldn't concentrate in class. C．She was laughed at by her classmates. D．She couldn't get on well with others. 5．What made Grimm have her own hair cut? A．Praise from her students. B．Devotion to her students. C．Request of Prisilla's mother. D．Suggestion from the hairstylist. 6．What can we know about Grimm?

A．She had her hair cut together with Prisilla. B．She expressed her sincere thanks to her pupils. C．She hesitated a lot before having her hair cut. D．She won a gold medal for facing difficulties bravely. 7．What is the text mainly about? A．How Grimm helped her student out. B．What problem Prisilla had at school. C．Why Prisilla won the Month Award. D．When Grimm got her new hairstyle.

C

[2020·武汉调研]While elephants born without tusks (长牙) are not unheard of, they normally form just 2 to 6 percent of the population. However, that is not the case at Mozambique's Gorongosa National Park, where an astonishing 33 percent of

female elephants born after the country's conflict ended in 1992 are tuskless. While that may appear to be just a coincidence, Joyce Poole, an elephant behavior expert, has another theory. The researcher thinks we may be witnessing unnatural evolution of the species due to the constant hunting of elephants for valuable ivory.

Poole says before the country's 15-year-long conflict, the park was home to over 4,000 elephants. However, by the time the conflict ended in 1992, about 90 percent of them had been killed for ivory to get money. Of the less than 200 survivors, over 50 percent of adult females had no tusks. Therefore, it is not surprising that the park's tuskless elephant population has grown greatly.

This is not the first time researchers have observed a great change in the population of elephants. At Zambia's South Luangwa National Park and Lupande Game Management Area, areas which were heavily hunted in the 1970s and 1980s, 35% of elephants 25 years old or older and 13%of those younger than 25 are now without tusks. A 2008 study published in the African Journal of Ecology found that the number of tuskless females at the Ruaha National Park in Tanzania went from 10.5 percent in 1969 to almost 40 percent in 1989, largely due to illegal hunting for ivory.

The recent ban on ivory in both the US and China should help get rid of, or at least reduce, elephant hunting. However, scientists are not sure how long it will take for elephants with a higher rate of tuskless females, to change the_trend.

8．What is the probable cause of the phenomenon mentioned in Paragraph 1?

A．Illegal hunting. B．Constant farming. C．A pure coincidence. D．Natural evolution.

9．Why did people kill so many elephants during the conflict in Mozambique? A．To get money by selling ivory. B．To develop new decorations. C．To provide food for local people. D．To make ivory products.

10．Which of the following had the earliest record on tuskless elephants? A．Gorongosa National Park. B．South Luangwa National Park. C．Ruaha National Park.

D．Lupande Game Management Area.