I am having problem understanding the difference between んじゃないかと思った and んじゃないかと思う。 

As for んじゃないかと思った, I found the following examples:"忘れているんじゃないかと思った" and "間に合わないんじゃないかと思った"。

Moreover, in regards to んじゃないかと思う, I found these two examples: "断れたんじゃなかったかと思いますが" and "慎重なんじゃないかと思う".

To be honest, i found myself unable to translate these sentences and thus understanding the grammar behind them. Could you explain them to me?

I know かと思った that expresses that one thought/ was afraid that something would happen, but eventually it did not. However, despite being apparently similar they seem to hold a different meaning and usage.

  • Split this up for yourself. This is essentially 「xxんじゃないか」and 「」と思った。or と思う。
    – psosuna
    Dec 16, 2019 at 21:20

2 Answers 2


思った is past tense, whereas 思う is present tense. 思う would be used when communicating what you currently think/feel, whereas 思った would convey what you thought at the time of the subject in question. Expressing fears that turned out to be unfounded is indeed a common use of 思った, but it's hardly limited to that.


As it has already been stated the former is in the past tense whereas the latter is in the present/future tense.

忘れて/いる/ん/じゃない/か/と/思った : (I) thought (思った) isn't it (じゃないか) that (ん) (he) has/forgotten (忘れて/いる) : I wondered if he had forgotten it.

You can also understand it like this:

「間に合わないんじゃないか」と思った : (I) thought (と思った) "is it not that I will not make it in time ?". : I wondered if I would make it in time

Present tense is the same thing, but you understand it as "I think" instead of "I thought". You would be better off learning each part individually instead of trying to understand んじゃないかと思った as a whole expression.

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