when后面通常接短暂性动词和持续性动词 while 只接持续性动词，短暂性动词通常是过去式 持续性动词加ing
例如：my father was sleeping when i got up 或while my father was sleeping ,i got up .
when后面通常接短暂性动词和持续性动词 while 只接持续性动词，短暂性动词通常是过去式 持续性动词加ing
例如：my father was sleeping when i got up 或while my father was sleeping ,i got up .