なぜ日本人には難しい？ Why Is This Confusing for Japanese Speakers?
Japanese has verb forms that loosely correspond to both tenses, but they don't map perfectly onto English. This leads to common mistakes like saying "I have gone to Tokyo yesterday" instead of "I went to Tokyo yesterday." Understanding the core logic behind each tense will fix this once and for all.
The Simple Past — 過去形
Use the simple past when an action happened at a specific, finished point in time. The key signal: you know when it happened, or the time is clearly in the past.
- I ate sushi last night. → 昨夜、寿司を食べた。
- She studied English in 2020. → 彼女は2020年に英語を勉強した。
- We watched a movie yesterday. → 私たちは昨日映画を見た。
Time words that signal simple past: yesterday, last week, last year, in 2010, ago, when I was a child
The Present Perfect — 現在完了形
Use the present perfect (have/has + past participle) when the action has a connection to the present. You're either talking about experience (ever/never), recent news, or something that started in the past and continues now.
- I have eaten sushi. → 寿司を食べたことがある。（経験）
- She has studied English for five years. → 彼女は5年間英語を勉強している。（継続）
- I have just finished work. → 仕事が終わったばかりだ。（直近の完了）
Time words that signal present perfect: ever, never, just, already, yet, recently, for, since
Quick Comparison Table
| Feature | Simple Past | Present Perfect |
|---|---|---|
| Specific time mentioned? | ✅ Yes | ❌ No (usually) |
| Connection to now? | ❌ No | ✅ Yes |
| Japanese nuance | 〜した (finished action) | 〜したことがある / 〜している |
| Example keyword | yesterday, last year | just, ever, since, for |
The Most Common Mistake — and How to Fix It
❌ "I have seen that movie last week."
✅ "I saw that movie last week."
The word "last week" pins the action to a specific finished time, so simple past is required. Whenever you have a specific time expression, choose simple past — every time.
Practice: Which Tense Is Correct?
- "She ___ (live) in Osaka for three years." → has lived (継続中)
- "We ___ (visit) Kyoto in March." → visited (特定の時点)
- "I ___ (never / try) Thai food." → have never tried (経験)
- "He ___ (call) you an hour ago." → called (1時間前＝特定の過去)
まとめ Summary
The golden rule: specific finished time = simple past; connection to the present = present perfect. Keep this rule on a sticky note on your phone screen and check yourself every time you write an English sentence. With a little daily practice, this distinction will become automatic.