D
Earth is the third planet from the sun. It is one of the four inner planets. The other three inner planets are Mercury, Venus, and Mars. The inner planets are also called the rocky planets, because they are made of rocks.
Earth is often called the “Water Planet”, because it is the only planet in our solar system which has liquid water on its surface. About 70% of the surface of Earth is covered by water! The other part of Earth is made up of continents and islands which have different landforms on them. Examples of landforms are mountains and plains. Plants and animals can live on Earth, because it has so much water.
Earth spins very quickly compared to other planets. It only takes Earth 24 hours to spin around its axis one time. One Earth day is 24 hours long! Earth orbits the sun in 365 days! This makes one Earth year 365 days long!
Earth is the only planet in our solar system where humans, other animals, and plants can live. There is plenty of water to drink or to live in. Water is present on Earth in its big oceans and in the air! Clouds are made of water vapor. The atmosphere has a lot of oxygen in it for animals to breathe, but the rest of our “air” is made up of water vapor, nitrogen, carbon dioxide, and other gases. The air is perfect for plants to grow. Earth temperature is not the same in all places, but the temperature is just right for plants, animals, and humans in most places on Earth.
Like the other inner planets, Earth has volcanoes. Volcanoes on Earth are different from those on other planets, because they still erupt. Scientists think that there may be active volcanoes on other planets and moons in our solar system, but they are still studying this.
Earth has one planet which we call the Moon. The surface of the Moon has many craters on it These were caused when meteorites hit it. It has many volcanoes on it which do not erupt anymore. We can see the moon at night without using a telescope. It is the closest space object to our planet ,Earth.
68.Earth is called the Water Planet,______.
A. because animals need water         B. the water makes it look blue from space
C. it has liquid water on its surface      D. Earth is the third planet from the sun
69. It takes Earth ______to orbit the sun in one year.
A.24 hours                   B.24 days                     C.365 days                   D.360 days
70. Life exists on Earth,______.
A. because the water, air, and temperature are just right
B. there is water vapor in clouds
C. Earth is the planet closest to the sun
D. earth has volcanoes
71.The craters on the moon were caused by______.
A. meteorites hitting its surface              B. active volcanoes
C. volcanoes which do not erupt anymore      D. some reasons that are not mentioned

For years , many people would not believe that smoke could attack so many parts of the body in so many ways . Study shows , however , that tobacco isn’t one single thing .  At least 60% of it is gas—20 different kinds of gas . And one of these is the deadly carbon monoxide (CO) （一氧化碳）.
In factories , the amount of this gas in the air is measured , and it must be kept under fixed , safe level . But there is 640 times this safe amount in cigarette smoke .
Oxygen is carried through your body by the red blood cells . But this poison gas , CO, will get to the blood cells before the oxygen can . So , if you smoke your blood carries five to ten times more of this deadly gas than is normal . To make up for this , your body must make more red cells .
The oxygen in your blood passes into your tissues（组织）. But here again CO makes trouble . It keeps the oxygen from passing into your tissues as fast as it should . Because of this , cigarette country is always about 8000 feet above sea level . Someone who smokes and lives at sea level gets as little oxygen as a nonsmoker at an altitude（高度）of nearly two miles .This happens to everyone who smokes , no matter how old or how young . Anyone who competes in sports can tell you that those who smoke run out of breath more quickly than those who do not .
1．The gas amount in cigarette smoke is______________.
A．640 times higher than the gas safe levels in factories
B．640 times lower than the gas safe levels in factories
C．640 times as much as that in factories
D．as dangerous as that in factories
2．If you smoke , ______________ .
A．your blood carries more oxygen than is normal
B．your blood carries much more CO than is normal
C．you can have five to ten times of blood than usual
D．your blood will be poisonous
3．Those who smoke______________.
A．all live at sea level
B．don’t live at an altitude of two miles
C．breathe as much oxygen as non-smokers
D．only get the same amount of oxygen at the sea level as non-smokers at an altitude of nearly 2 miles
4．Smokers are______________.
A．easily hurt              B．easily excited      C．easily tired         D．healthy

阅读下列句子，用所给单词或短语的正确形式填空

单词拼写（共10小题；每小题0.5分，满分5分）
根据下列句子及所给单词的首字母，在答题卷上按题号写出各单词的正确形式（每空限填一词）。
【小题1】 C___________ drove me inside.
【小题2】 Fresh air is of great b___________ to our health.
【小题3】 It’s important to know your own strengths and w___________.
【小题4】China and Japan have mid-autumn festivals, when people a__________ the moon and in China, enjoy mooncakes
【小题5】Many a child ___________ to death in Africa because of the lack of food last century.
【小题6】 At the beginning of the year, farmers usually have a lot of a___________ work to do.
【小题7】 The c__________ of some European countries are quite different from ours.
【小题8】 Without p___________, you cannot take photos here.
【小题9】 He managed to save the d___________ girl, which was praised by many people.
【小题10】The famous “ Oprah Winfrey Show” is b___________ live every Friday on CNN.

People and the sources of air pollution are found in the same places. This means that cities with large populations have the biggest problem of dirty air. Air pollution is caused by many different things. A major source of air pollution is the gas fumes from cars. Statistics show that 93 percent of all auto trips are within cities. Another major source of dirty air is the burning of coal and oil for energy. This energy is needed to make electricity. Of course, much more electricity is used in the city than in the country.
On the average, we throw away more trash and garbage than the year before. The burning of garbage contributes to air pollution. Many major industries are also responsible for the dirty air in the around cities. The fumes from iron, steel, chemical, and petroleum production add particles to the air.
The effects of air pollution range from mild headaches to death. The levels of pollution found in heavy for traffic may cause headaches for loss of clear vision. Wherever coal and oil are used for fuel, fumes may kill trees and plants and cause metal to corrode. In some of the larger cities, these fumes endanger the live of human beings by contributing to lung diseases and causing early death.
【小题1】The key point of the passage is that _________.