～たことがある

RuleVerb ta-form + koto ga aru: past experience, "have done (before)."

Curiosity

"ate" (simple past) and "have eaten (before)" (experience) differ. How do you express experience?

Intuition

Add "koto ga aru" (there is the act of) to the ta-form. Literally "the act of having done X exists (in my record)" = experience. It stresses "I have ever done it," not a one-time past.

Visualization

iku (dictionary) → itta (ta-form) → itta koto ga aru (experience). It passes through the ta-form.

行くdictionary form

Essence

Form it as ta-form + koto ga aru. Negative/question: koto ga nai / koto ga arimasu ka. Use it for vague past experience; it does not pair with a specific time (yesterday, last week) — those take the simple past.

Examples

日本へ行ったことがある。

I have been to Japan.

寿司を食べたことがありますか。

Have you ever eaten sushi?

その映画は見たことがない。

I have never seen that movie.

Mini-quiz

From "noboru" (to climb Mt. Fuji), how do you say "have climbed (before)"?