-제가 사람을 잘못 봤어요.

I got the wrong person. -> He's not the person I thought he was.

=> Another way: Your sentences are okay and these are other ways of saying them. 

A. Is it possible to have a healthy life style in modern world?

_{Due to air pollution and stressful heavy workload, many people are exposed to health hazard in modern society.}

_{In spite of these some diseases, medical scientists have discovered the solution for them, thanks to astonishing medical development. So, we can improve our health if we take care of ourselves}

 B. Make these sentences into English.

 (11/22/21)

-너무 분위기에 휩쓸리지 말아요.

Don't be carried along by the atmosphere. -> Don't get carried away.

-속단하기는 일러.

 It's too early to make a hasty conclusion.

>     Don't jump to any conclusions.

-제가 사람을 잘못 봤어요.

I got the wrong person. -> He's not the person I thought he was.

=> Another way: Your sentences are okay and these are other ways of saying them.