Analyzer
Sentence analysis
6Spans
Sentence
Span Details
手紙
letter; notenoun
を
object markergrammar
ポスト
postbox; mailbox; post; position; assignment; goalpost; online post; post-noun, suru verb, noun-modifying
に
direction, time, indirect object, or target markergrammar
投函
mailing; postingnoun, suru verb
した。
light/support verb with a noun or noun-like phrase-> するgrammar