单选题 When it ______ air pollution, Wuhan faces the three "C" s, cars, coal and construction, which lead to its severe air pollution.

A、 refers to
B、 comes to
C、 happens to
D、 speaks to

【正确答案】 B

【答案解析】[解析] 谈到空气污染时，武汉面临着三个“C”，即汽车、煤和建筑，这些导致武汉的空气受到严重污染。
本题考查动词短语辨析。refer to提及，提到；come to谈到，涉及；happen to碰巧；speak to跟…讲话。When it comes to...意为“涉及，谈到”，符合题意。故选B。