Can vs Could Exercise

Fill in the blanks with could, can, couldn't, can't.

1. In my first year as a teacher, I almost lost my self-confidence because I teach anything.
2. Mary tried hard to persuade her friend but she change her mind.
3-4. Bijan says he speak four languages but he talk to customers yesterday as he was a bit nervous.
5. Adan and her mother open the door because it was locked.
6. I finally talk to John after I tried to reach him on the phone for hours.
7-8. I never memorize all of the rules in the past, and I do it now either.
9-10. Mike was the only one who understand me, but now he either.
11. Before the nuclear disaster in the 1980's, people grow everything in their gardens.
12-13. No matter how hard I try, I see the difference in the two pictures Susan says she easily see.
14. We choose our opponents. The teams will be matched randomly.

Correctness =
Correct answers: