把I am in Grade Six and Kate is in Grade Four改为同义句

有没有变化格式要求?否则有很多种变化可能,比如：

= I am in Grade Six, which is two grades above Kate's.
= I am in Grade Six, (which is) two grades higher than Kate.
= Kate is in Grade Four, which is two grades below mine.
= Kate is in Grade Four, (which is) two grades lower than I/me.
= Kate and I are in different grades.
= Kate and I aren't in the same grade.

注：（ ）表示其内部分可以省略不写,/ 表示可以任意选用其一.