Grammar · N4
〜と思う and quoted thoughts
Use と to package a proposition before 思う and related verbs.
In short
A plain clause + と思います means “I think that…”. Nouns and な-adjectives generally include だ in the plain quoted clause: 学生だと思います.
How it works
The quoted content can express belief, prediction or opinion. Politeness usually sits on 思います, while the inner clause remains plain.
Useful contrast
This is the same quotation particle と used before 言う, 聞く and other speech/thought verbs.
Examples
明日は雨が降ると思います。
I think it will rain tomorrow.
これは便利だと思います。
I think this is convenient.
Common pitfall
Do not make the inner verb polite just because the whole sentence is polite; *行きますと思います is normally incorrect.