THE CATS HAD BEEN FED (BY ANN) BEFORE SHE WENT TO THE CINEMA

13. - GIÁN ÁN BAI TAP VE CHUYEN DE BI DONG(CO DAP AN)
GIÁN ÁN BAI TAP VE CHUYEN DE BI DONG(CO DAP AN)

13.The cats had been fed (by Ann) before she went to the cinema.