1. As (시간)
두 가지 일이 동시에 일어날 때 as를 사용합니다:
I watched her as she opend the letter. (I watched와 she opened는 동시에 발생한 사건입니다.)
As they walked along the street, they looked in the store windows.
어떤 일을 하고 있는 중간에 다른 일이 발생하는 상황에도 as를 사용합니다:
Jill slipped as she was getting off the bus.
The theif was seen as he was climbing over the wall.
위 예문들과 같은 경우에 as는 while과 같은 의미입니다.
종종 두 개의 짧은 행위가 동시에 일어날 때 as를 사용합니다:
We all waved good-bye to Liz as she drove away in her car.
(we waved와 she drove away는 동시에 일어난 일입니다.)
Turn off the light as you go out, please.
오랜 시간에 걸쳐 두 가지 일이 함께 변화할 때도 as를 사용합니다:
As the day went on, the weather got worse.
I began to enjoy the job more as I got used to it.
아주 짧은 한 순간을 이야기할 때 just as를 사용합니다:
Just as I sat down, the phone rang.
I had to leave just as the conversation was getting interesting.
as는 두 가지 일이 동시에 동시에 일어날 때만 사용하고, when은 어떤 일이 다른 일 다음에 일어날 때 사용합니다:
When I got home, I took a bath. (= not as I got home, but after I got home)
As I walked into the room, the phone started ringing. (= at the same time)
2. As (이유)
as는 경우에 따라 "because"와 같은 의미로 사용됩니다:
As it was a national holiday, all the banks were closed. (= because it was a national holiday)
We watched TV all evening as we had nothing better to do.
since도 같은 방식으로 사용됩니다:
Since it was a national holiday, all the banks were closed.
as가 시간의 의미일 때 행위나 사건과 함께 사용합니다.(see secation a):
I watched her as she read the letter.
as가 because와 같은 의미일 때는 상황과 함께 사용합니다:
As I was sleep, I didn't hear the bell. (= because I was sleep)
As they live near us, we see them quite often. (= because they live near us)
while과 when의 비교:
the bell rang while (or when) I was sleep. (not as I was asleep)
they got married when (or while) they were living in London. (not as they were living)