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野球部， やきゅうぶ
1. baseball club (at a university, corporation, etc.), baseball team
tbd
弟， おとうと， てい
1. younger brother, little brother, kid brother
2. brother-in-law (spouse's younger brother or younger sister's husband)
3. pupil, apprentice
弟弟，小弟，小兄弟；姐夫/妹夫（配偶的弟弟或妹妹的丈夫）；学生，学徒
は
1. indicates sentence topic
2. indicates contrast with another option (stated or unstated)
3. adds emphasis
指示句子的主题；表示与另一选项（无论是否明确提及）形成对比；表示强调
に
1. at (place, time), in, on, during
2. to (direction, state), toward, into
3. for (purpose)
4. because of (reason), for, with
5. by, from
6. as (i.e. in the role of)
7. per, in, for, a (e.g. "once a month")
8. and, in addition to
9. if, although
tbd
