Bài 5: Điền “ could” hoặc “couldn’t” vào chỗ trông trong các cấu sau. 1. When I was young, I _______play the guitar: it was too difficult for me! 2. Her grandmother was bilingual: she _______ speak both English and Spanish. 3. Yesterday, Peter ________ do that exercise alone. So, he called me for help. 4. In 1950, people ________ use mobile phones. 5. When his mother was young, she ________ skate but she can’t do it any longer. 6. We ________ open the door: it was locked from the inside! 7. In 1990, people ________ watch TV. 8. Mary’s grandfather ________ play chess and he was the best! 9. In1945, people ________ play video games. 10. But the ________ play chess! 11. Peter ________ play tennis last Monday: he had broken his arm! 12. When Ann was teenager, she ________ watch a horror film: it was too frightening for her! 13. Last Sunday, we ________ take any photos in the museum: it was forbidden. 14. Mozart ________ play the piano when he was 5. mong mọi giúp em với ạ :