mise de binsen o katte, tomodachi ni tegami o kakimashita.

direct object particle

Breakdown of mise de binsen o katte, tomodachi ni tegami o kakimashita.

• 友とも達だち: friend
• で: location particle
• 買かう: to buy

Questions & Answers about mise de binsen o katte, tomodachi ni tegami o kakimashita.

Why is で used after 店?

で marks the place where an action happens.

• 店で = at the store / in the store
• The action of 買う happens there, so で is the correct particle.

Compare:

• 店で買いました = I bought it at the store
• 店に行きました = I went to the store

So に often marks a destination, while で marks the location of an action.

Why is を used after 便せん and also after 手紙?

を marks the direct object of a verb — the thing directly affected by the action.

In this sentence:

• 便せんを買って = bought stationery / writing paper
• 手紙を書きました = wrote a letter

So both nouns are objects, but they belong to different verbs:

• 買う takes 便せん
• 書く takes 手紙

That is why を appears twice.

What is the difference between 便せん and 手紙 here?