ago-since

a / an

abbreviations

about / on

able

about to do /
on the verge of /
on the point of

above / over

according to

across / over

act / action

ago / since / for

all / all of

all / every

all / whole

almost / nearly

aloud / loudly

also / too / as well / as well as

A.M. / P.M.

among / between

another

any / no

around / about

as / like

as it is / as it was /
as it were


	ago / since / for

A.	ago는 과거에 발생한 것에 대하여 말하고자 year, month, day, time 같은 단어 다음에 사용되며 ...전에 라는 의미로 쓰인다.
1.	A long time ago, this area was a forest.
2.	That happened years ago.
3.	I moved here eight years ago.
4.	A long time ago, dinosaurs lived in this area.

B.	since는 특정 시점이나 사건과 함께 ...이후 (지금까지), ...로부터 (지금까지) 라는 의미로 사용된다.
1.	I've been waiting since three o'clock.
2.	I've been waiting since 2:30.
3.	She has been happier since she moved here.
4.	Since leaving college, he's lived with his parents.

X	I've been waiting from 2:30.
O	I've been waiting since 2:30.

C.	for는 과거나 미래에서 기간(amounts of time)을 나타내는 단어와 함께 ...동안 이라는 의미로 사용된다.
1.	I have been waiting for three hours.
2.	The building will last for years.

A long time ago, dinosaurs lived
in this area.

I've been waiting since three o'clock.

I have been waiting for three hours.