托福考试

【单选题】It is a popular notion that autumn leaves are tinted by freezing temperatures. In truth, the foliage is dulled, not colored, by frost. Red leaves such as maples are brightest when sunny days are followed by cool--but not freezing--nights. Under such conditions, sun- made sugars are trapped in the leaves, where they form the red pigment anthocyanin. Leaves that appear yellow in autumn are no less yellow in spring and summer. However, in spring and summer the yellow pigments--carotenoid and xanthophyll--are masked by the green pigment chlorophyll, which breaks down with the diminishing sunlight of fall.
The word masked in the passage is closest in meaning toA．created
B．colored
C．captured
D．concealed

网考网参考答案：D
网考网解析：
Masked means concealed in this context. Clues:Leaves that appear yellow in autumn are no lesssyellow in spring and summer. However, in springand summer the yellow pigments...are by thegreen pigment chlorophyll The yellow pigmentsdo not appear in spring and summer because thegreen pigment conceals them. document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>