2．原因状语
过去分词(短语)作原因状语，相当于一个原因状语从句，多位于句首，偶尔也出现在句尾或句中。
Moved by the heroic deeds，the children couldn't help crying.
孩子们被英雄事迹感动，情不自禁地哭了起来。
Lost in thought, he almost knocked into a tree.
由于陷入了沉思，他差点撞到树上。
The child well brought up by his parents behaves very well.
由于受到父母很好的教育，这个孩子举止规矩有礼。
3．条件状语
过去分词(短语)作条件状语，相当于一个条件状语从句，可以在其前加上if，unless，once等，多位于句首，该状语可能是对过去被动动作的假设，也可能没有具体的时间性，表示一种客观情况。
Given more time，we could do it better.
＝If (we were) given more time，we could do it better.
多给我们点时间的话，我们会做得更好。(对过去被动动作的假设)
Heated，water will turn into steam.
＝If (it is) heated, water will turn into steam.
如果受热，水会变成水蒸气。
