while引导时间状语只能用be
while引导时间状语只能用be doing吗？
doing吗？
while引导时间状语用be doing。中文意思是“一边做……一边做……”/正当做某事的时候。
例如，正当妈妈做午饭的时候，我在书房看小说《林海雪原》。
While my mother was making lunch, I was reading the novel Lin Hai Xue Yuan in my study.
在老师们的带领下，小学生们边走边唱朝去自然博物馆参观。
Under the guidance of the teachers, the pupils went to visit the Nature Museum while they were singing 。
until和while的区别？
一个是当型循环,一个是直到型循环.
while当型:当条件成立时进入循环.
until直到型:不管条件是否成立时,都先执行一次.之后进行条件判断
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。
My mother is cooking while my father is reading the newspaper .
She fell asleep while she was doing her homework .
2 名词 意为 一会儿 after a while for a while
After a while,she came back .
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。
She fell asleep when she was doing her homework .
I was walking in the street when I saw a wallet on the ground .
I saw her singing in the room when I passed by her room .
until 的用法
1 until是连词 引导时间状语从句
两个句型： ......(肯定句）until.... ...否定句）until ....
They worked until it was dark .他们一直工作凌晨一点。
He didnt go until the boys parents came back .直到那个男孩的父母回来了，他才走。
2 介词 They kept him waiting until oclock in the afternoon