词汇用法

定语从句：代词/名词/数词﹢of which/whom

①I was given three books on cooking, _________　_________　_________　_________ I really enjoyed．(它们中的第一本)

② have many friends, _________　_________　_________ are businessmen．(他们中的一些)

③It is reported that two schools, _________　_________　_________ are being built in my hometown, will open next year．(它们两个)