2．表原因，可转换为as，since或because等引导的原因状语从句。 Deeply moved by the story，the excited people stopped quarrelling with each other. ＝Because they were deeply moved by the story，the excited people stopped quarrelling with each other. 激动的人们被那个故事深深地感动了，停止了争吵。 3．表条件，可转换为if，once或unless等引导的条件状语从句。 If heated，water can be turned into vapour. ＝If it is heated，water can be turned into vapour. 水如果被加热，会变成水蒸气。