YOU SAID:

there is a huge cat in my living room that i've never seen before

INTO JAPANESE

居間には今まで見たことのない巨大な猫がいます

BACK INTO ENGLISH

There is a huge cat in the living room that I have never seen before

INTO JAPANESE

居間には今まで見たことのない巨大な猫がいます

BACK INTO ENGLISH

There is a huge cat in the living room that I have never seen before