单选题 Never before ______ so highly successful in changing his surroundings.
A. man has been B. man is C. has man been D. is man

【正确答案】 C
【答案解析】[解析] 在这之前，人类在改变其周边环境方面，从未如此成功。before提示本句应该用完成时，且因句首出现否定词never作状语，所以本句必须用倒装结构。