Modern Japanese doesn’t differentiate the simple and perfect tenses. The auxiliary verb た(だ) expresses them both.
- 今日は彼を見かけなかった -> I didn’t see him (all day) today. (Used only at the end of the day)
- これが今まで見た中で最高の映画だ -> This is the best movie I’ve ever seen
- こんなに美味しいラーメンは食べたことがない -> I’ve never had ramen this good before
The present perfect [have done] can be expressed with the continuous aspect ている as well.
- 彼はもう死んでいる -> He has already died, he is already dead
- 桜が咲いている -> The cherry trees have blossomed
- 今日は彼を見ていない -> I haven’t seen him today (so far)
- 彼は未だに分かっていない -> He still hasn’t understood
The past perfect [had done] are expressed with the continuous aspect ている+た as well.
- 彼はまだ分かっていなかった -> He still hadn’t understood
- 車はもう修理されていた -> The car had already been repaired
The present perfect continuous tense [have been doing] can be expressed with the continuous aspect ている. It is also often expressed with [verb 連用形+続けている]. The below are both “I have been working for the same company for 30 years” but the second one with 続けている has more emphasis on the continuity:
- 私は同じ会社で30年間働いている
- 私は同じ会社で30年間働き続けている
The helping verb 来た (来る+た of perfect) is often used as “from one point in the past until now”.
- 私は同じ会社で30年間働いて来た
- 私は同じ会社で30年間働き続けて来た (続けて来た is somewhat redundant, but common)
- 今まで努力して来た甲斐があった -> It has been worthwhile that I have worked hard until now
- 今まで我慢して来たが、もう限界だ -> I have been persevering until now, but I’ve reached the limit
- 国は傾いて来ている -> The country has been leaning, declining