本を買った

bought a book

→ 本
phrase Common #5,825
bought a book 本 means “book,” を marks it as the object, and 買った is the past tense of 買う (“to buy”). In questions, の can be added to ask for an explanation or confirmation, as in 本を買ったの? (“Did you buy a book?”).
JA: 昨日、新しい本を買った。
EN: I bought a new book yesterday.

彼女がその店で本を買った

She bought a book at that store.

動物についての本を買った

I bought a book about animals.

多くの生徒がその本を買った

Many students bought that book.

どんな本を買った

What kind of book did you buy?

私は見つけることができる日本に関するあらゆる本を買った

I bought every book about Japan that I could find.

昨日本を買った

I bought a book yesterday.

彼は書店数冊の本を買った

He bought several books at the bookstore.

私はその本を買ったとたんに後悔した

I regretted buying the book the moment I bought it.

私は子供たちに必要な本を買った

I bought the books the children needed.

私は今日たくさん本を買ったのでそれらを整頓した

I bought a lot of books today, so I organized them.