Usually といけない follows ない形 of 辞書形. For example,

  • 寝る前に、歯を磨かないといけない。I have to brush my teeth before sleeping.
  • 明日までに宿題を出さないといけない。I have to hand in my homework by tomorrow.

Today, I read a new grammar 辞書形+といけない. I really don't know what this grammar mean. For example,

  • 風邪を引くといけないから、暖かい服を着たほうがいい。
  • 子供が寂しがるといけないと思って、おもちゃで遊ばせておきました。
  • 子供に言い過ぎるといけないと思うが、すぐ口を出してしまう。

The book also provides other but similar meanings for each sentence above as follows.

  • ~引いてはから~ is equal to ~引くといけないから~
  • ~寂しがってはと思って~ is equal to ~寂しがるといけないと思って~
  • ~言い過ぎてはと思うが~ is equal to ~言い過ぎるといけないと思うが~

Any comments and suggestion are appreciated.

  • 2
    I think 引いてはから is a typo for something, but was not sure what the original sentence was like. Could you check that part?
    – naruto
    Apr 5 '16 at 16:03

I think that what is important to see here is that the と here is the conditional-と.

  • 歯を磨かないと…if you don't brush your teeth
  • 風邪を引くと…if you catch a cold

Next step is to understand the いけない part. You can see it as won't go (well) in the meaning of not good.

  • 歯を磨かないといけない…if you don't brush your teeth, that'll be not good. (Hence the meaning of: you must brush your teeth.)
  • 風邪を引くといけないから、暖かい服を着たほうがいい。…because if you catch a cold it will be no good, you'd better wear a warm piece of clothing. (Hence, you should wear a warm piece of clothing because you don't want to end up catching a cold.)

Here ては is a shortened version of てはだめだ・てはいけない・てはならない. Again, ては indicates conditional.

So 引いては~から ≒ 引いてはいけない ≒ 引くといけない

  • I ran a quick search and I could not find anything on ては being used as a conditional (that could be a question to ask). But you can find this same ては in てはどうか? (読んでみてはどうか -- what about reading it?) [[also ては is used as a conditional in 古文 even if it may not be relevant here]]. Apr 5 '16 at 15:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.