请问定语从句中的先行词what,which,whom,分别用在什么情况下 ?如何...答:He seems not to have grasped what I meant, which greatly upsets me. 他似乎没抓住我的意思,这使我心烦。 Liquid water changes to vapor, which is called evaporation. 液态水变为蒸汽,这就叫做蒸发。 4. 有时as也可用作关系代词 5. 在非限定性定语从句中,不能用关系副词why和关系代词that,而用who,...