Explanation
Use the present perfect when something happened during a time period that is not finished yet, or is still continuing, like today or this week.
For example, "I have already finished my homework today." Here, "I" is the subject, "have finished" is the present perfect verb form, and "already" means the action happened before now. "Today" is important because the day is still open, so English uses the present perfect, not the past simple. Japanese often says the same idea with a past-form verb, like "今日はもう宿題を終えた," but English shows the link to the unfinished time in the verb form. Use this pattern with words like "today," "this week," "this month," and "this year."
「今日」や「今週」のように、まだ終わっていない、あるいは現在も続いている期間中に何かが起こった場合は、現在完了形を使います。
たとえば、"I have already finished my homework today." では、"I" が主語、"have finished" が現在完了の形、"already" が「もう、すでに」を表します。"today" が大事で、今日という時間はまだ終わっていないので、英語では過去形ではなく現在完了を使います。日本語では「今日はもう宿題を終えた」のように過去形に見える言い方でも自然ですが、英語では未完了の時間とつながっていることを動詞の形で表します。"today," "this week," "this month," "this year" などと一緒によく使います。
Examples
- I have already finished my homework today. 今日はもう宿題を終えました。
- She has not called me yet. 彼女はまだ電話をくれていません。
- Have you seen Ken today? 今日はケンに会いましたか。
- We have had two tests this week. 今週はテストが2回ありました。
- The train has not arrived yet. 電車はまだ到着していません。
- I have visited that café three times this month. 今月はそのカフェに3回行きました。
- We've already eaten lunch today. 今日はもう昼食を食べました。
Common Mistakes
Japanese learners often use the past simple with an unfinished time word, for example, "I ate lunch already today." In English, use the present perfect: "I have already eaten lunch today." If the time is finished, use the past simple, like "I ate lunch yesterday."
日本語話者は、まだ終わっていない時間を過去形で言ってしまいがちです。たとえば、"I ate lunch already today." は不自然です。正しくは "I have already eaten lunch today." です。時間が終わっているなら過去形、まだ続いているなら現在完了を使います。