手紙, てがみ
letter, missive, note, mail
ここにあなたあての手紙が何通かあります。
を
Particle
1. indicates direct object of action
2. indicates subject of causative expression
3. indicates an area traversed
4. indicates time (period) over which action takes place
5. indicates point of departure or separation of action
ポスト
1. postbox, mailbox, mail box, pillar box
2. post, position
3. post (e.g. goalpost)
Noun or verb acting prenominally
4. post- (e.g. post-Cold War)
いったんポストに入れたものは、郵便局の所轄になる。
に
Particle
1. at (place, time), in, on, during
2. to (direction, state), toward, into
3. for (purpose)
4. because of (reason), with
5. by, from