20. A. changes B. tips C. researches D. differences

第二节 （共 10 小题；每小题 1.5 分，满分 15 分） 阅读下面短文，在空白处填入 1 个适当的单词或括号内单词的正确形式。

　　All kinds of birds will fly to your yard daily if you provide these three basic needs. In order to attract the largest 1 (various) of birds, offer several kinds of foods. Cardinals will feast on sunflower seeds, Chickadees favor black oil sunflower seeds, and Blue Jays just can't resist shelled peanuts. If you want to keep it simple, a good quality bird seed mix will satisfy most birds. And don't forget about the feeding station, 2 combines the four basic feeder types

　　___3 (attract) many birds. There are two tubes for small and large seeds. A hopper (漏斗) feeder, a suet feeder, and a platform feeder. Shelter is 4 key factor too. Birds are more likely to stay in your yard between 5 (meal) if you provide protective places to rest. Evergreen trees and jungles and favorite 6 (hide) places. So are brush piles. ______7 is of great importance to provide constant access 8 fresh water in a backyard bird habitat. This is critical during the winter when most 9 (nature) sources are frozen. There 10 (be) a dozen heated bird bath options available or you can use a small heater to keep water from freezing an irregular bird bath. By providing these three basic needs-food, shelter and water-birds are willing to concentrate in your backyard.