摘要： of 2. do 3 that 4. unless 5. an 6. Moreover/ Furthermore 7. personal 8. there 9. to develop 10. from Passage (10) There are two main reasons 1 the temperature of the air is always 2 change). One reason is that the air around you moves in from somewhere else . Air usually moves in large bodies 3 air masses. Some air masses move in from the north. These air masses usually have cold air that cause the temperature 4 . Air masses also move in from the south. They usually have 5 air that causes the temperature to rise. Temperature changes during the day or night can be great 6 small. This depends partly 7 how many clouds are in the sky. 8 there are many clouds during the night, they act like tile covers on your bed. They blanket the earth and keep the air from losing much of 9 heat. The temperature usually does not drop much during such a night. When there are many clouds during 10 day, some of the sun's energy will not reach the earth. The temperature usually does not rise much on such a day.
Thomas Jefferson, the third President of the United States, lived over 200 years ago, 1 many of his ideas are still of great 2 to us．
“Go and see!”In Jefferson's 3 , knowledge can be obtained(获得)from many sources including books and personal investigation．While a committee was discussing the 4 of a river, he made an on-the-spot measure of the depth．
“You can learn from everyone．”Although 5 to the top social status(地位), he went out of 6 to talk with people of humble origins(出身卑贱的)and even went into 7 to learn from them．
“ 8 for yourself!”Jefferson didn't accept blindly other people's opinions 9 careful thought．He wrote to his nephew,“neither believe nor 10 anything．”
“Do 11 you believe is right．”He treated criticsim(批评)in a scientific 12 ．He received much criticism but never answered his critics．In his opinion, he never listened to only one 13 ．There are two sides to every question．Listen to 14 , then decide which is better．
“Trust the future and trust the young．”He felt that 15 should never be limited to customs 16 have lost their usefulness．
17 being a well-known statesman, Jefferson was a thinker, an architect, a scientist and an inventor． 18 , he was the author of the Declaration of Independence．American education 19 a great debt to him．Owing to(由于)his great 20 in his work, he was respected and admired．