YOU SAID:
The wall shall be built.
INTO JAPANESE
壁は造られなければならない。
BACK INTO ENGLISH
The walls must be built.
INTO JAPANESE
壁は建設されなければなりません。
BACK INTO ENGLISH
The walls must be constructed.
INTO JAPANESE
壁は建設されなければならない。
BACK INTO ENGLISH
The walls must be constructed.
That didn't even make that much sense in English.