` 1 ` has been
` -> ` Ta chia thì HTHT + since : S + have / has + VPII + since + 1 mốc TG / QKĐ
` -> ` DHNB : since last night
` 2 ` : go
` -> ` Ta chia thì HTĐ : S + Vs/es
` -> ` DHNB : sometimes
` 3 ` : have - studied - have studied
` -> ` How long + have / has + S + VPII ?
` -> ` HTHT + for : S + have / has + VPII + for + 1 khoảng TG
` 4 ` saw
` -> ` Cấu trúc : S +last + V-ed / V2