問題詳情

請依下文回答第 46 題至第 50 題：     The ozone layer is a region in Earth’s stratosphere that contains high concentrations of a bluish gas called ozone.Although ozone constitutes only about one-millionth of the 46 gases, it absorbs most of the sun’s ultravioletradiation. Without the ozone layer, this radiation would destroy all life on the surface of the planet.     Ultraviolet radiation creates and perpetuates ozone. Because an ozone molecule is struck by an ultraviolet ray, itfalls apart, 47 free oxygen. An oxygen atom can combine with another free oxygen to 48 more ozone, andthis cycle absorbs most UV radiation.     Some manufactured chemicals interfere with this cycle, thus reducing the amount of ozone in the stratosphere.Among the worst offenders are chlorofluorocarbons (CFCs), usually found in refrigerants and aerosol sprays and nowgenerally 49 due to their harmful effects. Falling ozone levels have caused a thinning of the ozone layer aboveAntarctica, 50 the ozone hole. The Antarctic ozone hole has increased dramatically in size over the past twodecades. A smaller hole over the Arctic is now developing.
46
(A)atmosphere’s
(B)rendezvous’s
(C)iceberg’s
(D)ravine’s

參考答案

答案：A
難度：適中0.5
統計：A(2),B(1),C(1),D(0),E(0)

內容推薦

內容推薦