Days are longer ______ summer than ___________ winter.

    There are many reasons for it. When the sun __2__, it is day. When the sun sets, it is night. Days are warmer than nights. This is __3__ the sunshine falls on the earth during the day. The sunshine makes the land, the water and the air warm. At night when the sun is not there, it is __4__. In the mornings and in the evenings the sunshine is slanting(斜射). So it is not very hot. At noon the sunshine falls __5__ on the earth, and it is very hot.

    We know that the earth goes __6__ the sun. When one half of the earth is close to (就近) the sun, the other half is __7__ from it. The part of the earth closer to the sun is summer. Here the days are warmer and longer. And the part of the earth away from the sun is winter. Here the days are cooler and __8__. For example, when it’s winter in China, it is summer in Australia.

    People can __9__ the weather, too. We know the temperature on the earth is getting warmer and warmer. This is because the environment has been polluted and destroyed . Now the weather is much worse than before. It’s very terrible. If we want to __10__ our environment, something useful should be done immediately.

(    )1. A. must　　   B. can’t　　       C. may　　        D. should

(    )2. A. rose　　    B. rises　　        C. rising　　       D. sets

(    )3. A. why　　  B. because　　    C. how　　        D. when

(    )4. A. cooler      B. coolest　　      C. hot　　　　     D. hottest

(    )5. A. straight     B. straightly        C. slant　　       D. slanting

(    )6. A. over　　  B. in　　　　      C. round　　      D. below

(    )7. A. off　　   B. wide　　       C. high　　        D. away

(    )8. A. long　　    B. short　　       C. shorter　　     D. longer

(    )9. A. get　　     B. be　　　　     C. become　　    D. change

(    )10. A. improve  B. improves        C. improved        D. improving

The word “day” has two meanings. When we talk about the number of days in a year, we are using “day” to mean 24 hours. But when we talk about day and night, we are using “day” to mean the time between sunrise and sunset. Since the earth looks like a ball, the sun can shine on only half of it at a time. Always one half of the earth is having day and the other half night. A place is moved from day into night and from night into day over and over by the spinning（旋转）of the earth. At the equator（赤道）day and night are sometimes the same length（长度）. They are each twelve hours long. The sun rises at 6 o’clock in the morning and sets at 6 o’clock in the evening. For six months the North Pole is tilted（倾斜）toward the sun. In those months the Northern Hemisphere（半球）gets more hours of sunlight than the Southern Hemisphere. Days are longer than nights. South of the equator nights are longer than days. For the other six months the North Pole is tilted away from the sun. Then the Southern Hemisphere gets more sunlight. Days are longer than nights. North of the equator nights are longer than days. Winter is the season of long nights. Summer is the season of long days.
（  ）6.When the Western Hemisphere is having day, the Eastern Hemisphere is having ________.
　　     A. both day and night              B. day
　　     C. neither day nor night            D. night
（  ）7. A place is moved from day into night and from night into day over and over by ________ of the earth.
　　     A. the pushing                    B. the pulling
C. the spinning                    D. the passing
（  ）8. At the equator day is as long as night ________.
　　        A. sometimes     B. never       C. usually        D. always
（  ）9. When the North Pole is tilted toward the sun, the Northern Hemisphere gets ________ sunlight.
　　    A. less           B. more       C. all            D. no
（  ）10. When it is winter in China,  ________.
　　    A. the USA is tilted toward the sun
　　    B. the South Pole is tilted away from the sun
　　    C. the North Pole is tilted toward the sun
　　    D. the North Pole is tilted away from the sun