Hoàn thành câu với thì quá khứ đơn hoặc thì hiện tại hoàn thành 1. In 1976, 60% of families (be) ...couples with children but by 1996 this ( fall) to 51% 2. Several senior employees(leave) ... thr company bu the time the new manager (arrive)....last week 3. Until the new software ( purchase)..., the staff ( struggle).....to keep accounts up to date 4. I (see) ...... that movie three times last year .I (see) it again last night 5 when my supervisor ( popin) ........my office the other day l ( work )....... the project for nearly three hours