1．①Worried about the journey, I was unsettled for the first few days.
②Given better attention, the trees could grow better.
③Described as an enormous round plate, it spins slowly in space to imitate the pull of the earth's gravity.
2．①Hit by a lack of fresh air, my head ached.
＝Because I was hit by a lack of fresh air, my head ached.
②I stared at the moving model of the waste machine, absorbed by its efficiency.
＝I stared at the moving model of the waste machine, and was absorbed by its efficiency.
3．①When offered help, one often says “Thank you” or “It's kind of you.”
②The research is so designed that once begun nothing can be done to change it.
[我的发现]
(1)作状语用的过去分词(短语)和句子的主语之间有逻辑上的动宾关系，或称为被动 关系。
(2)第一组句子中的过去分词(短语)分别在句子中作：①原因状语；②条件状语；③伴随或方式状语。
(3)比较第二组句子可知，作状语用的过去分词(短语)可以转化成相应的状语从句或并列句。
(4)从第三组句子可知，表示时间、条件、方式、比较或让步的状语，可用“从属连词＋过去分词”结构。可用于该结构中的从属连词有：when, once, while, if, unless, as if, as, than, though, although等。
