When expressing one's thought, feelings, opinions, ideas and guesses, "~ to omou (I think that ~)" is frequently used. The particle "to" indicates that the preceding sentence or words are a quotation.
Since "~ to omou" always refers to the speaker's thoughts, "watashi wa" is normally omitted.
| Ashita ame ga furu to omoimasu. 明日雨が降ると思います｡ | I think it will rain tomorrow. |
| Kono kuruma wa takai to omou. この車は高いと思う｡ | I think this car is expensive. |
| Kare wa furansu-jin da to omou. 彼はフランス人だと思う｡ | I think he is French. |
| Kono kangae o dou omoimasu ka. この考えをどう思いますか｡ | What do you think about this idea? |
| Totemo ii to omoimasu. とてもいいと思います｡ | I think it is very good. |
If the content of the quoted clause expresses one's intention or speculation about a future event or state, a volitional form of a verb is used preceding "~ to omou." To express a thought other than one's volition or opinion toward the future, a plain form of a verb or adjective is used preceding "~ to omou" as shown in the examples above.
| Oyogi ni ikou to omou. 泳ぎに行こうと思う｡ | I think I'm going to swim. |
| Ryokou ni tsuite kakou to omou. 旅行について書こうと思う｡ | I think I will write about my trip. |
To express a thought or idea you have at the time of your statement, "~ to omotte iru (I am thinking that ~)" is used rather than "~ to omou."
| Haha ni denwa o shiyou to omotte imasu. 母に電話しようと思っています｡ | I'm thinking of calling my mom. |
| Rainen nihon ni ikou to omotte imasu. 来年日本に行こうと思っています｡ | I'm thinking of going to Japan next year. |
| Atarashii kuruma o kaitai to omotte imasu. 新しい車を買いたいと思っています｡ | I'm thinking that I want to buy a new car. |
When the subject is a third person, "~ to omotte iru" is used exclusively.
| Kare wa kono shiai ni kateru to omotte iru. 彼はこの試合に勝てると思っている｡ | He thinks he can win this game. |
Unlike English, the negation "I don't think" is normally placed within the quoted clause. It is possible to negate "~ to omou" such as "~ to omowanai," however, it expresses stronger doubt, and is close to the English "I doubt that ~."
| Maki wa ashita konai to omoimasu. 真紀は明日来ないと思います｡ | I don't think Maki is coming tomorrow. |
| Nihongo wa muzukashikunai to omou. 日本語は難しくないと思う｡ | I don't think Japanese is difficult. |
