時の副詞節 - Adverb Clauses of Time
SINCE
【SINCE】は過去のある時点から今までという意味です。この場合、主節は現在完了形と使われる事が多いです。前置詞として使うこともできます。
I have not seen him since we graduated from college.
How long is it since we last went to the theater?
I've changed jobs since then.
【SICNE】にはBECAUSEの意味もあるので注意しましょう。
Since we were in the area, we stopped by and met them.
AFTER と BEFORE
"AFTER" "BEFORE"は、副詞節を導いて「〜の後」、「〜の前」という意味になります。
After I (had) turned off the lights, I left room.
Before I left room, I (had) turned off the lights.
"AFTER"と"BEFORE"は、完了形を使わなくても時間の前後を節で表せます。
I need to tell you before I leave.
You can watch TV after you finish your homework.
ただし、動作が「完了」している事を示す時は、完了形を使います。
After I had done the project, I called you.
She had learned English before she moved to New York.
After I have done the project, I will call you.
She will have learned English before she moves to New York.
UNTIL/TILL と BY THE TIME
UNTIL/TILL と BY THE TIME は、「〜まで」という意味です。
until, tillはある時点までずっと行為は続き、それ以降は続かない時に使います。「〜までずっと」という意味です。
by the timeはある行為が、ある時点の前に終了している時に使います。「〜までに」という意味です。
He stayed there until we arrived.
He will stay there until we arrive.
He had left there by the time we arrived.
He will have left (will leave) there by the time we arrive.
"BY THE TIME" は、常に主節の行動が副詞節の行動より前になります。過去の行為の場合、必ず、主節は過去完了を使います。
WHEN 節 は、過去完了か過去形かで動作の順番が前後しますが、BY THE TIME の場合時間関係は固定されています。
He had already left by the time we arrived there.
×He left by the time we arrived there.
動作の順番：1:去る 2:到着
He had already left when we arrived there.
動作の順番：1:去る 2:到着
He left when we arrived there.
動作の順番：1:到着 2:去る
We will start a party by the time he arrives here.
We will have started a party by the time he arrives here.
動作の順番：1:パーティ 2:到着
We will start a party when he arrives here.
動作の順番：1:到着 2:パーティ
