YOU SAID:

I am in school and will never understand anything

INTO JAPANESE

私は学校にいて、何も理解しません

BACK INTO ENGLISH

I am in school and do not understand anything

INTO JAPANESE

私は学校にいて何も理解していません

BACK INTO ENGLISH

I do not understand anything at school

INTO JAPANESE

私は学校で何もわからない

BACK INTO ENGLISH

I do not know anything at school

INTO JAPANESE

私は学校で何も知らない

BACK INTO ENGLISH

I do not know anything at school