一般情况下,有逗号的表示转折,= whereas, and in constrast, 翻译为“而...”.也可通过逗号前后两句的意思判断while的含义.
Ex. The spirit is willing, while the flesh is weak. 心有余而力不足.
没有逗号,表示同时.= at the same time that, 在...的同时
Ex. Please do not interrupt me while I'm speaking. 我说话的时候请别打断我.
When有while和whereas两个意思：
Ex. When I was young, I was sick all the time. 我小时候是个病秧子.（表示延续）
Ex. She stopped talking when she ought to have spoken for herself. （表示转折）该她为自己说话的时候,她却不说了.