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JLPT N3 · Compound verbs & suffixes

通(とお)す (toosu)

~通す — “do ~ all the way through”

In short · The suffix 通す attaches to the masu-stem of a verb and means to keep doing the action all the way to the end, without stopping or giving up. It is used for persistence or for finishing something from beginning to end.
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Pattern

  • 動詞ます形の語幹 + 通す masu-stem + 通す (言い通す, 読み通す, やり通す)

Meaning and connection

Remove ます and add 通す: 言う → 言い通す, 読む → 読み通す, やる → やり通す. 通す originally means “to pass through,” so the action is carried through from one end to the other.

Two nuances

With opinions and attitudes, it means holding firm despite pressure: 意見を言い通す. With long tasks, it means finishing from start to end: 最後まで読み通す. Both stress stamina and will.

Common words

Frequent combinations include やり通す, 言い通す, 読み通す, 守り通す, 走り通す, 貫き通す. It is a fixed set; do not attach it freely to any verb.

Examples

  • 彼(かれ)は自分(じぶん)の意見(いけん)を最後(さいご)まで言(い)い通(とお)した。

    Kare wa jibun no iken o saigo made iitōshita.

    He stuck to his opinion all the way to the end.

  • 最後(さいご)まで読(よ)み通(とお)すのに、一週間(いっしゅうかん)かかった。

    Saigo made yomitōsu no ni, isshūkan kakatta.

    It took a week to read it all the way through.

  • 一度(いちど)決(き)めたことは、最後(さいご)までやり通(とお)す性格(せいかく)だ。

    Ichido kimeta koto wa, saigo made yaritōsu seikaku da.

    Once I decide something, I'm the type to see it through to the very end.

Common mistakes

  • Attach to the masu-stem, not the dictionary form: 読み通す, not 読む通す.
  • It is a limited set of combinations. For others, use 最後まで〜続ける.

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