初中英语语法:现在分词和过去分词的用法答:2)“while ( when, once, until, if , though等连词)+分词”结构现在分词或过去分词作状语时,有时可以在分词前加while,when, once, although, until, if等连词。【例如】When leaving the airport, she waved again and again to us.While waiting for the train, I had a long talk with...