YOU SAID:
my teacher is a science one
INTO JAPANESE
私の先生は理系です
BACK INTO ENGLISH
my teacher is a science major
INTO JAPANESE
私の先生は理科を専攻しています
BACK INTO ENGLISH
my teacher majors in science
INTO JAPANESE
私の先生は科学を専攻しています
BACK INTO ENGLISH
my teacher majors in science
You should move to Japan!