你提的这两个问题非常好！

第一个问题：交通灯从某一个颜色变为红色这个动作不是短暂性的吗？为什么它此时还可以用过去进行时并且与while 连用？

【答】非延续性动词，亦叫“终止性动词”或“瞬间动词”，其特点是动作一旦发生，就意味着完成和结束，不再延续。所以，这类动词不能跟“时间段”的状语连用，当然也不能跟while 连用。

在你的句子中，change 是延续性动词，不存在上述情况。尽管短暂，红绿灯的变化也是一个过程，所以使用进行时并跟while 连用，一点问题都没有。

 "Changing"  means  ... 10, 9, 8, 7, 6, 5, 4, 3, ...

第二个问题：become 能跟“since一段时间”连用吗？

【答】become 是“非延续性动词”，但有时可以跟“for+一段时间”连用，而跟since 连用则十分常见！这时，它表示动作发生在since 之时，之后的状态是从since 算起。例如：

She has become a teacher since 2006.  “自2006年以来她就当老师了。”

意思是说：She became a teacher in 2006 and has been a teacher since then.

关于become 跟since 连用的 例子，英语中比比皆是，例如：

I think the situation has become worse since the current government came into power.

我认为现任政府上台执政以来情况变的更糟糕了。

She has become active since last term.

从上学期来她开始变得积极了。

The study of myth has become hot since 1980s, but goddesses are still negleted .

上个世纪80年代以来神话研究逐渐成为显学，而女神研究依然较为寂寞。

This structure has become obvious since 2005.

这个结构在去年开始变得明显。

In fact Barbie has become a household name for many years.

事实上，芭比娃娃已经成为一个家喻户晓的名字了许多年。

A close friend of mine from China has become a Singapore citizen for some years. He manages his own business and can be considered fairly successful.

我有一位来自中国的熟人，多年前已成为新加坡公民，拥有自己的公司，应当说是卓有成就了。

My sister has become a college for three years.

我妹妹成为一个大学生已经三年了。

He has become an awful bore since she got married to him. 

她自从和他结婚后，就变得令人厌烦透了。

He's become increasingly withdrawn since his wife's death. 

他从妻子死后越来越孤僻了。

He's become very high and mighty since he got that new job. 

他自从得到了那份新工作后就变得神气活现。

She has become very food-minded since her holiday in France. 

 她自法国度假回来，对食物就很讲究了。

He's become a lot more domesticated since his marriage. 

他婚后变得非常恋家。

The export market have become very difficult since the rise in the dollar.

从美元的上涨以来，出口市场变得非常困难。

Since her death, she has become a cult figure.

她死后成了部分人狂热崇拜的偶像。

The trends since the 1950s have become even more marked.

20世纪50年代以来，这些趋势更加显而易见。

She has become very sophisticated since she went to live in London.

移居伦敦后她变得世故多了。

Since then, the contrast between his two careers has become even more pronounced.

从那时起，他的两种职业之间的差距变得愈加明显。