in Grade Seven 还是at Grade Seven

是we are all in （Grade） seven还是we are all in （grade) seven i am in grade eight,not grade seven. I’m a student in Grade Seven. 应该是 She in Seven Grade ,Four Class I'm in Class Four ,Grade Seven . ____she___Class seven,grade Three? I am in Grade Seven.对Geade Seven提问 Mary is in Grade Seven(对seven提问) Jane is in Grade Seven.Lily is in Grade Seven,too.(改为同义句） Jim and Tony are in Grade Seven.对in Grade Seven提问 i am in grade eight,not grade seven.那are you in geade seven Jane is in Grade Seven.Lilyis in Grade Seven,too.（改为同义句）