As the industry developing in these years most of
污水
已帮助 人
As the industry developing in these years,most of the rivers have been 【contaminated】 by sewage （污水）.
A.polluted
B.downgraded
C.mixed
D.blackened
-
答案：A
contaminate：污染，弄脏。题干意思为：近年来随着工业的发展，多数河流被污水污染了。pollute：污染，腐蚀; downgrade：使降低，降级；mix:混合，结合；blacken：使变黑，弄黑。经过比较，pollute与contaminate意思相近，所以选择A。