1.先行词是something,anything,nothing,all,none,few,little,much等代词时,关系词只能用that.❶Hereissomething(that)Iwilltellyou.❷Thereisnothingintheworldthatcanfrightenhim.❸Allthatcanbedonehasbeendone.2.当先行词被形容词最高级和序数词修饰时。❶Thisisthemostinterestingstory(that)Ihaveeverheard.❷Thefirstplace(that)theyvisitedinLondonwastheBigBen.3.当先行词即有人也有物时,只能用that。Icanrememberwellthepersonsandsomepictures(that)Iseeintheroom.4.先行词是theone时,关系词用that。Isittheone(that)youwant?5.当主句已有疑问词who或which时,从句用that,避免重复。Whoisthegirlthatwonthefirstplace?6.先行词被theonly,theevery修饰时,关系词用thatIt’stheonlyword(that)Iknowinthepassage.