非常好奇为什么会有这类练习?实际意义有多大?老师的教案目的是什么? 　　下面的例子并不表示我支持这类毫无实际意义的语法练习. 　　Yesterday Iaskedthosewhodidnotwanttositinmygrammarclasstoleavewithcredits. 　　Thosewhodidnotwanttositinmygrammarclassyesterday wereaskedtoleavewithcredits(byme). 　　Thestudents(whom)theofficerequirestotakemyclassshouldreporttoRoom319by8amtomorrow. 　　Thestudentswho are requiredtotakemyclass(bytheoffice)shouldreporttoRm319by8amtomorrow. 　　Weinvitetheteacherswhosestudentsaretakingvacationsnowtocometojoinusforfunthisafternoon. 　　Theteacherswhosestudentsaretakingvacationsnowareinvitedtocometojoinusforfunthisafternoon.