1. When I was young, I couldn't play the guitar: it was too difficult for me!
2. Her grandmother was bilingual: she could      speak both English and Spanish.
3. Yesterday, Peter couldn't do that exercise alone. So, he called me for help.
4. In 1950, people could   couldn't use mobile phones.
5. When his mother was young, she could       skate but she can't do it any longer.
6. We could   couldn't open the door: it was locked from the inside!
7. In 1900, people could   couldn't watch TV.
8. Mary's grandfather could     play chess and he was the best!
9. In 1945, people could   couldn't play video games.
10. But they could    play chess!