If you want to state what you think you can put と思います at the end of a sentence. However I noticed that sometimes you're supposed to put だ before と思います so that it becomes だと思います, and sometimes you're not. How do you know when to put だ before と思います and when to leave it out?

5 Answers 5


The と (to) of と思います works like the quotes in English. So the part before と must be a valid sentence.

○ 美しい   と思います
× 美しい だ と思います (美しいだ is not a valid sentence)
○ 美しいんだ と思います (very strong feeling)

○ キレイだ と思います
○ キレイ  と思います

  • 1
    You need だ after キレイ
    – Lukman
    Commented Jun 4, 2011 at 14:49
  • 5
    キレイと思います is perfectly fine Japanese, ask any native or look for google.
    – Uberto
    Commented Jun 4, 2011 at 18:31
  • 1
    I think it's important for us to know that きれい, being a ~na adjetive, it should be followed by です/だ (even if people don't used it). Commented Sep 17, 2011 at 4:36
  • 1
    As Daniel says, there is a pattern. イ-adjectives shouldn't be followed by a だ/です, while ナadjectives should be (optional in speech).
    – Jeemusu
    Commented Oct 31, 2012 at 3:27
  • 1
    キレイと思います is NOT perfectly fine Japanese, although there are native speakers who say it. As Uberto put it, "the part before と must be a valid sentence", which is because と indicates a sort of quotation. Because 「キレイ。」is not a complete sentence (it's a truncated one, you can say), キレイと思います sounds awkward.
    – Ryo
    Commented Apr 28, 2017 at 6:46

Don't think of the だ as a part of it. 「だと思う」 is just 「と思う」 stuck to the end of a sentence that happened to end in だ.

The only time you might need to add an extra だ is if you use it as a colloquial-ish stand-alone reply in the same way as 「だね。」 and whatnot.

  • heys btw what do you mean by this?: The only time you might need to add an extra だ is if you use it as a colloquial-ish stand-alone reply in the same way as 「だね。」 and whatnot.
    – Pacerier
    Commented Jun 24, 2011 at 18:51
  • @Pacerier: You can "reply" to statements by saying things like 「だね。」 or 「だと思うな。」, which is all grammatically wrong but language is like that. I guess you could imagine a 「そう」 at the beginning of the sentence if you want to. Commented Jun 25, 2011 at 0:42
  • ok got it =D
    – Pacerier
    Commented Jun 25, 2011 at 10:13

From Tae Kim's Guide To Japanese @ http://www.guidetojapanese.org/learn/complete/verb_phrase :

A verb clause can be phrased by adding 「と」 to the end of the clause. For verb clauses that end in an plain noun or na-adjective, we must add 「だ」.

So 「だ」 needs to be added before 「と思う」 if the last word in the clause we want to quote is a noun or na-adjective. Some examples of mine:

I'll be fine in the exam, I think.

Teacher's daughter is pretty, I think.

The person that made a mistake is the other party, I think.

If the last word is a verb or an adjective, you skip the 「だ」:

I thought it is a bit expensive so I did not buy it.

It is a bit expensive but I think I am going to buy it anyway.

There is one condition where you also skip the 「だ」 before a quotative 「と」, that is if you are quoting a name or a term, for example:

I am called Lukman.

That person is being called "Red Devil" around this area.

  • btw according to your answer きれいと思います should be wrong, but Uberto above claims that it's acceptable.. i'm wondering what are your thoughts on this issue?
    – Pacerier
    Commented Jun 25, 2011 at 10:13

Each time you can write のです then you can write のだ.

Then you can combine this (using と) with a variety of verbs including: 思う、信じる、言える。。。

Here is what should be your thinking process when building a sentence:

  • "This is not correct." (less formal, more blunt):

    正しくない。 (tadashikunai)

  • "This is not correct.":

    正しくないです。 (tadashikunai desu)

  • "I think this is not correct.":

    正しくないと思います。 (tadashikunai to omoimasu)

  • "This is not correct." (attenuating with の):

    正しくないのです。 (tadashikunai no desu)

  • "I think this is not correct." (with の, the sentence you're asking about):

    正しくないのだと思います。(tadashikunai no da to omoimasu)

  • "I think this is not correct." (spoken form):

    正しくないんだと思います。(tadashikunai n da to omoimasu)

As a short explanation, I wrote の = attenuation but this is not completely true. Depending on the context it can be used to emphasize the action that appears before の, to make your point...etc. Most of the time it is used in sentences like:


You can also use だと思います if there is a noun or anything that is not a verb before.


  • 2
    だと思います doesn't work with 難しい. I don't understand why from reading your explanation. Commented Jun 4, 2011 at 10:05
  • 3
    You don't use だ with any i-adjectives (難しい, 高い, さびしい etc).
    – nevan king
    Commented Jun 4, 2011 at 10:18

きれい is a な-Adjective and not a い-Adjective.

Therefore, it should be: きれいだと思います。

  • な-Adjective+ だ と思います

    日本語の勉強は大変だと思います。 I think Japanese study is tough.

  • い-Adjective と思います

    日本語の勉強はおもしろいと思います。 I think Japanese study is interesting.

  • Noun+ だ と思います

    あの人はセンターの学生だと思います。 I think that person is a student at the centre.

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