通す (toosu) conjugation
to let pass, to overlook, to continue
通す (とおす, toosu) is a godan verb. Godan verbs change their final kana up and down its column of the kana chart — the a-row for negatives, the i-row before ます, the e-row for potential and ば. Every form below is tappable — hear it, then say it back.
Conjugation table
| Form | Plain (casual) | Polite (~ます) | When you use it |
|---|---|---|---|
| Dictionary / plain | 通す toosu | 通します tooshimasu | The form you look up. Also the casual present and future. |
| Plain negative | 通さない toosanai | 通しません tooshimasen | “doesn’t / won’t”. From here it conjugates like an i-adjective. |
| Plain past | 通した tooshita | 通しました tooshimashita | The casual past — same ending as the te-form, with た/だ. |
| Plain past negative | 通さなかった toosanakatta | 通しませんでした tooshimasendeshita | “didn’t”. The negative past, still i-adjective-shaped. |
| Te-form | 通して tooshite | — | The connector: requests, linking clauses, ~ている. |
| Progressive (~ている) | 通している tooshiteiru | 通しています tooshiteimasu | “is ~ing”, or an ongoing resulting state. |
| Desire (~たい) | 通したい tooshitai | 通したいです tooshitaidesu | “want to ~”. Behaves as an i-adjective. |
| Volitional | 通そう toosou | 通しましょう tooshimashou | “let’s ~” / “I think I’ll ~”. |
| Potential | 通せる tooseru | 通せます toosemasu | “can ~”. What you could do; the object often takes が. |
| Passive | 通される toosareru | 通されます toosaremasu | “is ~ed”. Also the honorific and the suffering passive. |
| Causative | 通させる toosaseru | 通させます toosasemasu | Make or let someone do it. |
| Causative-passive | 通させられる toosaserareru | 通させられます toosaseraremasu | Be made to do it — the long one. |
| Imperative | 通せ toose | 通してください tooshitekudasai | Blunt order. Use ~てください in real life. |
| Prohibitive | 通すな toosuna | — | “don’t!” — dictionary form + な. |
| Conditional (~ば) | 通せば tooseba | — | “if ~”. General rules and hypotheticals. |
| Conditional (~たら) | 通したら tooshitara | — | “if / when ~”. The everyday conditional. |
🔊 Tap any Japanese word to hear it spoken.
Why it conjugates this way
Godan verbs change their final kana up and down its column of the kana chart — the a-row for negatives, the i-row before ます, the e-row for potential and ば.
See the full rules on the verb conjugation guide.