AT 2 O’CLOCK YESTERDAY, MY SISTERS... THE FLOOR.A. CLEANED B...

10. - TONG HOP KIEN THUC TIENG ANH THCS VA CAC BAI KIEM TRA THU
TONG HOP KIEN THUC TIENG ANH THCS VA CAC BAI KIEM TRA THU
10. At 2 o’clock yesterday, my sisters... the floor.A. cleaned B. was cleaning C. cleans D. were cleaning III. Dựng từ gợi ý viết lại cỏc cõu sau sao cho nghĩa khụng đổi.