只讲解这三个单词做动词的用法如下：1.require 1）require sth (of sb)2）require sb to do sth3）require doing 主动表被动4）require that-clause〔虚拟语气：(should)+V原〕2.demand1）demand sth of/from sb2）demand to do sth；demand to be done3）demand that-clause〔虚拟语气：(should)+V原〕3.request1）request sth of/from sb2）request sb to do sth3）request that-clause〔虚拟语气：(should)+V原〕
