問題詳情
請依下文回答第 46～50 題Many US bird populations are in decline, some of which are even on the brink of extinction. Of the 800 species ofbirds in the United States, 67 are listed as endangered or threatened; another 184 are listed as “species of conservationconcern” because they have small distribution, are facing high threats or have a declining population. Hawaiian birds andocean birds appear most at risk. More than one-third of all US bird species are in Hawaii. However, 71 Hawaiian specieshave gone extinct since A.D. 300 and about 10 species have not been seen in the past 40 years. The declines of US birdpopulations can be traced to a variety of factors, including agriculture, climate change, unplanned urban development,and overfishing. In the grasslands, for example, intensified agricultural practices have hurt bird populations. Grasslandcannot support many birds if it is overused or burned too frequently. Besides, public lands and parks are mowed toofrequently and the grass is too short to provide a habitat for birds.While many bird species are in decline, some other species are thriving. Research shows that wetland bird speciesbegan to increase in the late 1970s, which reflects the importance of the artificial habitats to the survival of many birdpopulations. The results prove that investment in wetlands has paid off and that it is now necessary to invest similarly inother neglected habitats where birds are undergoing steepest declines.
【題組】46 What is this passage mainly about?
(A) Variety of bird species in Hawaii.
(B) The decline of bird species in the US.
(C) The habitat of bird species in the US.
(D) The need for stricter bird protection laws.
參考答案
答案：B
難度：適中0.544444
統計：A(6),B(49),C(17),D(12),E(0)