英语定语从句 求主句、从句、先行词、以及关系代词在句子中做什么成分 1)Humans are destroying nature day by day,_______of course,will cause punishment sooner or later. 2)A war is so cruel that it always causes great losses,as has happened in Iraq and other countries. 3) Earth is a rocky planet where liquid water which is necessary for life,can exist.