Đọc kỹ câu hỏi và đáp án trước khi làm bài.
Câu 1. My grandparents walk _____ twenty minutes a day.
Câu 2. How long is it _____ you visited your grandparents?
Câu 3. We have been dating _____ a long time.
Câu 4. That lady has been waiting for the bus _____ noon.
Câu 5. I studied for this test _____ three days straight.
Câu 6. My family has lived here _____ last March.
Câu 7. She has worked there _____ she finished college.
Câu 8. I have been calling you _____ half-an-hour.
Câu 9. Lisa and Jill have been at the library _____ a long time.