while的用法
1连词引导时间状语从句,意为当.时候while引导的句子的谓语部分必须是可以延续的动词或结构.
Mymotheriscookingwhilemyfatherisreadingthenewspaper.
Shefellasleepwhileshewasdoingherhomework.
2名词意为一会儿afterawhileforawhile
Afterawhile,shecameback.
when的用法
when连词意为当...时候...这时.引导时间状语从句,与while不同,when引导的句子的谓语部分可以是短暂性的也可以是持续性的动词或结构.
Shefellasleepwhenshewasdoingherhomework.
IwaswalkinginthestreetwhenIsawawalletontheground.
IsawhersingingintheroomwhenIpassedbyherroom.
until的用法
1until是连词引导时间状语从句
两个句型:.(肯定句)until....否定句)until.
Theyworkeduntilitwasdark.他们一直工作凌晨一点.
Hedidn'tgountiltheboy'sparentscameback.直到那个男孩的父母回来了,他才走.
2介词Theykepthimwaitinguntilo'clockintheafternoon.