3、用,修饰名词或代词2.定语从句的引导词的三种功用:(1)引导定语从句(2)替代先行词(3)在定语从句中充当一定的成分。3.解题要领:根据定语从句中所缺成分来确定是用关系代词还是关系副词,决不要因先行词是时间名词就用when,是地点名词就用where。1.【2018·江苏】Self-driving is an area _______China and the rest of the world are on the same startingline.A.thatB.whereC.whichD.when【答案】B2.T