doing sth 作状语的分类 -ing形式作状语，可表时间、原因、结果、条件、让步、方式、 伴随状况等。 ﹡Seeing my parents waving in the crowd，I went running to them. ﹡Crossing the road, the old man was knocked over by a car. ﹡(When) Hearing the news, he got ...