YOU SAID:

The boy chases the ball

INTO JAPANESE

その少年はボールを追う

BACK INTO ENGLISH

The boy was chasing the ball

INTO JAPANESE

その少年はボールを追いかけていた

BACK INTO ENGLISH

The boy was chasing a ball

INTO JAPANESE

その少年はボールを追いかけていた

BACK INTO ENGLISH

The boy was chasing a ball