YOU SAID:

The past is a foreign country: they do things differently there

INTO JAPANESE

過去は外国です：彼らはそこで異なることをします

BACK INTO ENGLISH

The past is foreign: they do different things there

INTO JAPANESE

過去は異質です：彼らはそこで異なることをします

BACK INTO ENGLISH

The past is heterogeneous: they do different things there

INTO JAPANESE

過去は異質です：彼らはそこで異なることをします

BACK INTO ENGLISH

The past is heterogeneous: they do different things there