Quoting People

Sentences such as "I think..." or "He said..." are very common in daily speech, and it's fairly easy to translate both of those to Japanese.

If I want to say "I think...", then I add と思います to the end of my statement, where any verbs present must be in plain form.

スバル君はとってもかわいいと思います。
I think Subaru-kun is really cute.

明日テストがあると思います。
I think there's a test tomorrow.

カナトはお菓子が大好きだと思います。
I think Kanato loves candy.

リーさんは動物園に行ったと思います。
I think Lee-san went to the zoo.

アリスは兄弟がいないと思います。
I don't think Alice has any siblings.

In that last sentence, it's important to notice that in the Japanese version, I'm not actually saying "I don't think." In Japanese, it's more common to say "I think this is not true", rather than "I don't think this is true." For example:

ジムは大学生じゃないと思います。
I don't think Jim is a college student. (I think Jim is not a college student.)

トムは新しい車を買わないと思います。
I don't think Tom bought a new car. (I think Tom didn't buy a new car.)

If I want to quote someone's speech like "He said...", then I add と言っていました to the end of the statement. The progressive form used in that phrase means that I was there when I heard the person say it, as in "I heard them saying..."

I must also preserve the original tense when quoting someone, so if Jim says "I have work to do", then I would say "Jim said he has work to do", and NOT "Jim said he had work to do."

シュウは家に勉強しに行っていると言っていました。
Shuu said he's going home to study.

ジョンは今晩メアリーに会いたいと言っていました。
John said he wants to meet with Mary tonight.

レイジは食堂で昼ごはんを食べたと言っていました。
Reiji said he ate lunch in the cafeteria.

The same structure can also be used with similar speech-related words, such as 聞く and 答える.

映画を見ないと聞きました。
I asked if they wanted to see a movie.

アヤトとライトは「はい」と答えました。
Ayato and Laito answered "yes."