Fill in the blanks with the words given below. Change the forms where necessary. 1) Although cars help us travel fast from one place to another, they ________ the air we breathe(呼吸). 2) Most of the buildings in this city are quite low. Only in its very center can people see two __________ tall buildings by Times Square. 3) Forests ________ rainwater and so keep it from running off the land too rapidly(快速地). 4) Although light seems to travel across a room as soon as we open a window, it ________ takes some time to travel. 5) I’ve always believed that happiness ________ more than money. 6) The ________ of air can make a balloon filled with a light gas rise high above the earth because the balloon is lighter than the air outside it. 7) It was 39 _________ Celsius in the house and the fans could not cool the temperature at all. 8) A warm, ____________ jacket is the first thing you need for mountain walking. 9) It would cost about $5,000 to _______ a new heating system in a house like theirs. 10) Many people visit the national parks to see the plants and animals there or simply to enjoy a holiday and _____ in the quiet beauty. 11) Since the 1980’s, a lot of countries have worked hard to _______ the many problems of cities and towns. 12) This door is made of very _______ material(材料) and cannot be broken easily. 13) Kids often do the _________ of what their parents tell them to do because they want to see if they can succeed without their parents’ help. 14) My wife likes the color red very much and so I _________ the door of our new house bright red.