for a while 和 after a while 和once in a while 和 all the while的意思 和区别（求详解）

1.for a while ：for a period of time暂时；片刻；一会儿
*Wait for a little while,as I shallbe back in a few minutes．等一会儿,因为我马上就回来.
*Let's rest for a while．让我们休息一会儿.
*Why don't you lay that difficult math problem aside for a while 你为什么不把那道数学难题暂时放一边呢?
2.after a while 过一会儿,不久后
After a while,these people cooled off towards me.
过了一会儿,这些人对我态度冷淡了.
After a while,driving becomes second nature to you.
过不多久,开车的动作就像本能的反应一样了.
3.once in a while 偶尔,有时
occasionally；now and then有时；偶尔
*We go for a picnic in the park once in a while．我们有时去公园里野餐.
*Once in a while the puppy would run away．小狗有时也会溜出去.
4.all the while 一直,始终
He sang all the while they walked home.在他们回家的路上,他一路走一路唱.
We waited for three hours,all the while hoping that someone would come and fetch us.我们等候了三个小时,一直希望能有人来接我们.