YOU SAID:

human ate the grain that was being eating by the

INTO JAPANESE

人間は食べていた穀物を食べた

BACK INTO ENGLISH

Humans had was eating cereal

INTO JAPANESE

人間は穀物を食べていた

BACK INTO ENGLISH

He was eating cereal

INTO JAPANESE

彼は穀物を食べていた

BACK INTO ENGLISH

He was eating cereal