as time goes by 和 as time goes on有什么区别

1. “主短从长”型：即主句是一个短暂性的动作，而从句是一个持续性动作，此时三者都可用。如：

　　Jim hurt his arm while [when, as] he was playing tennis.

　　吉姆打网球时把手臂扭了。

　　As [When, While] she was waiting for the train, she became very impatient.

　　她在等火车时，变得很不耐烦。

　　注意：as用于引出一个持续性动词表示“在……期间”时，其谓语通常只能是那些含有动作和发展意味的动词，一般不能是那些不用于进行时态的动词，所以下面一句中的while不能换为as：

　　A：I’m going to the post office. 我要去邮局。

　　B：While you are there, can you get me some stamps?

　　当你在邮局时，能帮我买几张邮票吗?

2. “主长从长”型：即主句和从句为两个同时进行的动作或存在的状态，且强调主句动作或状态延续到从句所指的整个时间，此时通常要用while。如：

　　I always listen to the radio while I’m driving.

　　我总是一边开车一边听收音机。

　　He didn’t ask me in; he kept me standing at the door while he read the message.

　　他没有让我进去，他只顾看那张条子，让我站在门口等着。

　　但是，若主句和从句所表示的两个同时进行的动作含有“一边……一边”之意时，则习惯上要用as。如：

　　He swung his arms as he walked.

　　他走路时摆动着手臂。

　　I couldn’t remember a story to tell the children, so I made one up as I went along.

　　我想不出有什么故事可给孩子讲了，只好现编现讲。

3. “主长从短”型：即主句是一个持续性动作，而从句是一个短暂性动作，此时可以用as或when，但不能用while。如：

　　It was raining hard when [as] we arrived.

　　我们到达时正下着大雨。

　　When [As] he came in, I was listening to the radio.

　　他进来时，我在听收音机。

　　二、根据主句与从句动作是否同时发生来区分

1. 若主句与从句表示的是两个同时发生的短暂性动作，含有类似汉语“一……就”的意思，英语一般要用as 。如：

　　The ice cracked as [when] I stepped onto it.

　　我一踩冰就裂了。

　　He jumped to his feet as the boss came in.

　　老板一进来他立刻站了起来。

　　但是，在hardly [scarcely]…when…句式中，不能将when换成as。如：

　　Scarcely had we arrived, when it began to rain.

　　我们刚一到就下起雨来了。

都是时间的进行
as time goes by 强调失去的时光 As time goes by, I still miss you.
as time goes on 强调正在进行中的时间。 As time goes on, the game is almost over.