The Whale's Voyage Strange as it may seem，modern whales' ancestors didn't always live in the water.
（1）AA.Scientists have discovered new details about their ancestors and close relatives.
The journey whales made from land to water began about 50 million years ago.The dinosaurs had already disappeared.（2）BB.The mammals （哺乳动物） were warm-blooded.They had fur or hair to keep them warm，and they produced milk to nurse their young.
Some of these ancient mammals began to wander along muddy shores and explore the water.They were probably searching for food.（3）GG.Over time their bodies gradually adapted to an aquatic（水生的） life：Arms changed into flippers （鳍状肢）.Back legs got smaller and eventually disappeared.About 10 million years later，several species of these mammals had become fully aquatic.
（4）FF.For example，they remained warm-blooded，unlike fish.But they developed other features well suited to sea life.They lost most of their hair，which made their bodies more streamlined（流线型的）for swimming.They continued to breathe oxygen from the air，just like land animals.But their nostrils（鼻孔） gradually moved toward the top of the head，becoming blowholes（喷水孔）.
Fossils provided clues to the whales' past.The secret was locked in the skulls of their four- legged ancestors.Scientists found features similar to those of modern whales.
Examining early whales revealed another clue.（5）DD.But their anklebones（踝骨）were like those of today's two-toed hoofed（有蹄的） mammals-sheep，camels，deer，pigs，and hippos.
To determine which of the hoofed mammals are most closely related to whales，scientists also examined their DNA.Scientists soon found whale's nearest relative：the hippo!
A.Their ancestors lived on land.
B.But many ancient mammals survived the extinction.
C.The whale breathed in the same way as mammals.
D.These whales had tiny legs，too small to be useful for walking.
E.As to what caused the extinction，opinions were divided among scientists.
F.The newly aquatic mammals kept some characteristics from their ancestors' lives on land.
G.The ability to find new kinds of food in the water or live in a new environment gave these land animals an advantage.
【考点】传统习俗与文化．
【答案】A；B；G；F；D
【解答】
【点评】
声明：本试题解析著作权属菁优网所有，未经书面同意，不得复制发布。
发布：2024/5/27 14:0:0组卷：0引用：1难度：0.4
相似题
-
1．Imagine mountains enveloped in silver water，shining in the spring sun.Summer sees the mountains turn bright green with growing rice.During autumn，these mountains are gold，and in winter they are covered with white frost.（1）
These terraces（梯田） were built by the local Zhuang and Yao people.Starting in the Yuan Dynasty，work on the terraces took hundreds of years.（2）Reaching as far as the eye can see，these terraces cover tall mountains，often from the bottom to the very top.
（3）Firstly，there are few large flat areas of land in the region.Building the terraces could increase the areas to grow rice.Secondly，although the region has plenty of rain，the mountains are steep（陡峭） and the soil is shallow，The fat terraces help catch the rainwater and prevent the soil from being washed away.
But perhaps the most important is the way people have worked in peace with nature.The terraces are cleverly designed，with hundreds of waterways connecting with each other.During the rainy season.rainwater moves down the mountains and into the terraces along these waterways.The sun heats the water and turns it into vapour（水蒸气）.（4）These terraces also provide a perfect environment for birds and fish，some of which feed on insects harmful to crops.
Although modern technology helps produce more crops，these terraces still mean a lot to the local people for whom traditions hold much value.（5）Thus，new generations continue to use ancient methods of agriculture to maintain the terraces.Today，the Longji Rice Terraces attract thousands of visitors to admire this great wonder created by people and nature working together.
A.Terraces were built to collect the rain.
B.These are the colors of the Longji Terraces.
C.This knowledge is passed down through families.
D.It wasn't completed until the early Qing Dynasty.
E.So how did people change the entire mountains into terraces？
F.This forms clouds from which rain falls down onto the terraces again.
G.So why did these people take trouble turning the entire mountains into terraces？发布：2025/1/1 17:30:2组卷：3引用：4难度：0.5 -
2．A Comets are among the most beautiful and interesting（1）
（sight） in the universe.For centuries，people（2）（show） great interest in studying them.In 1682，Edmund Halley，an astronomer，noticed a comet that was especially bright and large.Based on his calculations，Halley predicted that this bright comet would return in 1758 or 1759-this was about 75 years（3）he first saw the comet.The comet really returned on time and it was named "Halley's Comet" in honor of Edmund Halley.
B
Emma was on her way home when she heard a sudden scream.Looking around，she saw a little boy on the sidewalk gasping（急喘） for air，his （4）（frighten） mother begging for help.Emma rushed to the boy，（5）face had turned purple. "What's wrong？" "A candy!In his throat!" It was lucky that Emma had learned how（6）（perform）the Heimlich maneuver（海姆利克急救法） at school.She acted quickly.Soon，the boy coughed up a piece of candy and began breathing again.He （7）（save） in time.
C In Japan，the word bonsai means tray plant.It refers to the interesting（8）（combine） of art and the planting and growing of miniature trees and plants.Bonsai originated in China more than 2，000 years ago and（9）（spread） to Japan about 700 years ago.Some people believe that only small plants must be used in bonsai，but this is not true.Nearly any type of tree or plant can be used，as long as it is grown （10）a seed or a small cutting.发布：2025/1/1 17:30:2组卷：73引用：4难度：0.7 -
3．Going to college is a new experience full of excitement of the unknown．Socialization （社交） is a big thing for college students and it is common to feel a little uncomfortable going into a situation where everyone is a stranger．You may probably miss your friends from high school．（1）
College is a great opportunity to make new lifelong friends．The question is：how？
▲Get to know your roommate．
You may find you have lots of things in common with your roommate，but even if you are completely different from each other，with a little effort and understanding the two of you may become best friends．
▲（2）
If you leave your door open，this shows that you welcome visitors．As a result people will naturally stop in and say hello．Closed doors are not likely to bring many visitors and those who stay locked up in their rooms may give others the impression of being cold．Other students will be less likely to stop in and build a new friendship．
▲Join clubs or organizations．
Getting involved in organized socialization is a great way to meet new people．（3）By staying active in college groups such as clubs and organizations you can meet lots of people with whom you share common interests．
▲Talk to classmates．
（4）Starting conversations in class is a great opportunity to meet people who are interested in the same kind of studies as you are．Short friendly discussions can build lifelong friendships．
▲Try out for a sport．
If you're athletic，trying out for a sport will do for you the same thing that joining a club will do．（5）
A．Close the door to keep away from theft．
B．Hang a welcome sign on your dorm room．
C．Your roommate is the first person you will have close contact with．
D．It also helps you get more familiar with the campus．
E．Get to know your classmates as you'll be spending several months with them．
F．You will instantly meet a large group of people who share your interests in sports．
G．Trying actively to find new friends can help ease （缓和） the feelings of being lonely．发布：2025/1/1 18:0:1组卷：17引用：4难度：0.9
