完了:ちょうど終わった / もう終わった
今、動作が終わったところ、またはすでに終わっていることを表します。 結果として今の状態に関係します。
目印語:just / already / yet
I have just finished my homework.
She has already left home.
Have you finished the report yet?
I haven't cleaned my room yet.
過去形:I finished my homework an hour ago. は「1時間前」が中心。
NG I have finished my homework yesterday.
OK I finished my homework yesterday.