____twice a year, whether it is a car or a bus or a truck, is the rule that every driver must obey in this city
A.Examining
B.Examined
C.Being examined
D.Having been examined
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C解析本题易误选B。考查动名词的用法，名中whether it is a car…为让步状语从句，is 为系词，故少主语。A、B、C、D中只有C可作主语表被动。