NOTHING UNUSUAL HAPPENED, ____________

20. - DE KIEM TRA TIENG ANH 11 CUOI NAM
DE KIEM TRA TIENG ANH 11 CUOI NAM
20. Nothing unusual happened, ____________?A. did they B. didn't they C. did it D. didn't itChoose the underlined word or phrase -A,B,C or D- that needs correcting.