YOU SAID:

I once saw a cat but you have to wear a hat

INTO JAPANESE

猫を見たことがありますが、帽子をかぶる必要があります

BACK INTO ENGLISH

I've seen a cat, but I have to wear a hat

INTO JAPANESE

猫を見たことがありますが、帽子をかぶらなければなりません

BACK INTO ENGLISH

I have seen a cat, but I must wear a hat

INTO JAPANESE

猫を見たことがありますが、帽子をかぶらなければなりません

BACK INTO ENGLISH

I have seen a cat, but I must wear a hat