Jack's love for birds started when he made his first birdfeeder about six years ago．He filled the feeder with seeds （种子），put it in his backyard and then （46 ）　　started coming．He got really （47）　　in birds as more came．Then be joined a local society．As he realized that more and more birds were dying very（48）　　，he wanted to try his best to help them．

Besides what he has done，he has his own group called Protecting Out Birds．He does （49）　　about birds，run a website to teach people about birds and how to help them，and （50）　　boxes for birds．Not long ago，he found that the bluebirds were nesting（做窝）in the dead trees which were often cut down，（51）　　he began to make bluebird boxes for the birds in order to save them．Now he wants to use these boxes to（52）　　the dead trees．He hangs these boxes up in trees and takes（53）　　down every week to see if the birds are nesting in them．He also writes articles，hoping that more people will （54）　　protecting natural ecosystems（生态系统）．"Researching birds is （55）　 to protecting birds，"jack says，"In order to protect birds，we have to learn and really know about the birds．"

46．A．bees	B．birds	C．people	D．scientists
47．A．nervous	B．weak	C．bored	D．interested
48．A．peacefully	B．safely	C．quickly	D．sadly
49．A．practice	B．business	C．instruction	D．research
50．A．builds	B．breaks	C．lifts	D．pushes
51．A．so	B．but	C．though	D．because
52．A．take good care of	B．take the place of	C．catch up with	D．come up with
53．A．it	B．this	C．these	D．them
54．A．wait for	B．send for	C．join in	D．hand in
55．A．simple	B．crazy	C．important	D．fresh