We can never expect bluer sky unless we stop industrial waste going into atmosphere.A.

We can never expect bluer sky unless we stop industrial waste going into atmosphere.
A. a; the; the
B. the; the; the
C. a; /; the
D. the; /; /

(答案→)A. a; the; theB. the; the; theC. a; /; theD. the; /; /解析：a blue sky 蔚蓝的天空，固定搭配。第二空特指工业的废物故加the ，第三空atmosphere 大气层前面加the.句意：除非我们阻止工业废物排放到大气层中，否则我们不可能期望有蔚蓝的天空。

这个解释是对的