………… DO THEY TRAVEL ABROAD

121. - BAI TAP TRAC NGHIEM ANH VAN CUC HAY CHO MOI CAP DOCO DAP AN DAY DU
BAI TAP TRAC NGHIEM ANH VAN CUC HAY CHO MOI CAP DOCO DAP AN DAY DU
121. A: ………… do they travel abroad? – B: Once a year. A. When B. How C. What time D. How often