YOU SAID:

Smoking should be illegal

INTO JAPANESE

喫煙は違法である必要があります

BACK INTO ENGLISH

Smoking must be illegal

INTO JAPANESE

喫煙は違法でなければなりません

BACK INTO ENGLISH

Smoking must be illegal.

INTO JAPANESE

喫煙は違法でなければなりません。

BACK INTO ENGLISH

Smoking must be illegal.