YOU SAID:

I have to study a lot of stuff for tomorrow

INTO JAPANESE

私は明日のために多くのものを勉強しなければなりません

BACK INTO ENGLISH

I must study a lot of things for tomorrow

INTO JAPANESE

私は明日のためにたくさんのことを勉強しなければなりません

BACK INTO ENGLISH

I must study a lot of things for tomorrow