that引导的宾语从句可以作动词、形容词等的宾语.主句中常见的谓语动词有say, know, hear, see, hope, think, believe, write, tell等.系动词加形容词afraid, worried, sure等后,也可用that引导的宾语从句. 如：I hope that he will come back soon. 我希望他能快点回来. 在由that引导的宾语从句中,由于连词that只起引导功能,无具体意义,不作句子成分, 因此在口语或非正式文体中常可省略,省略之后不影响原句性质和意义.