定语从句中:只用that而不用which的五种情况引导定语从句的关系代词有:that(指人或物),which(指物),who(指人)。指人时可用that或who;指物时可用that或which;但有时只能用that,不能用which。常见的情况有下列五种:1)当先行词是:all,any,anything,everything,nothingtheone,much,few,little或被它们修饰时。例如:IsthereanythingthatIcandoforyou?有什么可以为你做的吗?Allthatcanbedonemustbedone.凡是能做的都必须做。2)当先行词被形容词的最高级或序数词修饰时。例如:Thatisoneofthemostinterestingbooksthataresoldinthebookshop.那是这家书店出售的最有趣的书之一。Thefirstthingthatweshoulddoistogetsomefood.我们该做的第一件事是弄点吃的。3)当先行词有:theonly,thevery,thesame,thelast等修饰时。例如:Mynecklaceisnottheonlythingthat'smissing.我的项链不仅是丢掉的东西。4)当主句以who或which开头时,定语从句中引导词用that,不用which或who。以避免重复。例如:Whoisthegirlthatiswearingaredcoat?正穿一件红色外套的女孩子是谁?5)当先行词既有人又有物时,用that。例如:Thewriterandhisnovelthatyouhavejusttalkedaboutarereallywellknown.你刚才谈起的那位作家以及他的小说确实很著名。