1.由that引导的宾语从句。That只有语法作用，没有实在的意义，在口语和非正式文体中可以省略。例如：Hesaid(that)hewantedtostayathome.Shedoesn’tknow(that)sheisseriouslyill.Iamsure(that)hewillsucceed.2.由连接键卖代词who,whom,whose,what,which和连接副词when,where,why,how引导态绝的宾语从句。这些连接代词和连接副词在宾语从句中充当某个成分。例如：Doyouknowwho(whom)theyarewaitingfoe?Heaskedwhosehandwritingwasthebest.CanyoutellmewheretheNo.3busstopis?Idon’tknowwhythetrainislate.3.由if或whether引导的宾语从句。If和whether在句中的意思是“帆亮姿是否”。例如：Iwanttoknowif(whether)helivesthere.Heaskedmewhether(if)Icouldhelphim.
