Choose the correct answer in each sentence.
( Chọn từ đúng cho mỗi câu. )

1. Yesterday we can't , couldn't go to the beach. It rained all day.

2. Please turn down the music ! I can't , couldn't study.

3. Could , Can you speak English a few years ago.

4. I'm a fast typist. I can , could type 90 words-per-minute on my computer.

5. Sam could , can tell time when he was four years old.

6. Could , Can you finish the math test yesterday ?

7. Our neighbors can't , couldn't control their dog. She needs dog-obedience classes.

(Tư liệu tham khảo: Betty Schrampfer Azar . Understanding and Using English. 3rd ed.)