YOU SAID:

I am so bad at physics and never understand what this mans is saying

INTO JAPANESE

私は物理がとても苦手で、この人が何を言っているのか全く理解できません

BACK INTO ENGLISH

I'm very bad at physics and I can't understand what this person is saying at all.

INTO JAPANESE

私は物理がとても苦手で、この人が何を言っているのか全く理解できません。

BACK INTO ENGLISH

I'm very bad at physics and I can't understand what this person is saying at all.