This is the decision【 made by them.过去分词短语，后置定语】=This the decision 【that/which was made by them定语从句】意思，功能相同，结构不同。记住哦——过去分词短语中，没有be动词；
表示被动的 定语从句中，要用be动词。再如：A lake is an area of water 【surrounded by land.】=A lake is an area of water 【which/that is surrounded by land.】 祝你开心如意！...
