阿摩線上測驗
17. Functioning as a filter in the stratosphere, __________ from much ultraviolet
radiation.
(A)the ozone layer shields the earth's surface
(B)to shield the ozone layer of the earth's surface
(C)shielding the earth's surface is the ozone layer
(D)the Earth's surface and the ozone layer
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統計： A(55), B(4), C(14), D(2), E(0) #3262743
統計： A(55), B(4), C(14), D(2), E(0) #3262743
