... had excellent profits this quarter The class's understanding has increased greatly this semester Have they finished the report yet? Hành động khứ để lại kết The study of irregular verbs has improved ... ing I, You, He, She, We, They won't have been studying for long by the end of this class Nghi vấn Từ để hỏi (thường often 'How long') +will + chủ ngữ + have+ been + verb + ing How long will he, ... điểm Ví dụ: I've been reading this book since 10 this morning Từ thường kèm : for (with a period of time), since (with an exact point in time), ever, never, yet, already, this week (month, year)...