in 3rd grade 意味

• 《in (the) third [3rd] grade》3年生で
  Mary is now in (the) third [3rd] grade in elementary school. メアリーは今小学校の3年生だ。
  

例文

1. even though she told me she has a primary school son in 3rd grade
   何か小学校3年生の男の子が いるっていってたんだけど
2. although i am already in 3rd grade , i also eat sweets in a club room
   もう3年生なのに 部室でも ダラっとして お菓子 食べてるし
3. if it's a child , we have one as well . a girl in 3rd grade in middle school .
   子供なら うちにも いるよ。 中3だよ 女の子だ。