Grade 6 English worksheet focusing on the use of "could" and "couldn't" in sentences.

To solve this problem, we need to complete each sentence using either could or couldn't. The choice depends on the context of the sentence—whether the action was possible or not.

Solution:

1. Isabel _______ sing well when she was 4 years old.
- Context: It suggests that Isabel had the ability to sing well at a young age.
- Answer: could

2. When Anne was young, she _______ play the guitar.
- Context: This implies that Anne had the ability to play the guitar when she was young.
- Answer: could

3. When Jim was 7 years old, he _______ eat on his own.
- Context: This indicates that Jim had the ability to eat independently at the age of 7.
- Answer: could

4. We _______ take photos in the museum as it was not allowed.
- Context: The sentence states that taking photos was not allowed, so we did not have the ability to do so.
- Answer: couldn't

5. Anne and her parents _______ watch a nice movie on Netflix over the weekend, it was fun.
- Context: This implies that they were able to watch a movie, which was enjoyable.
- Answer: could

6. When Mr. Smith was young, he _______ run for 10 miles, now he can't.
- Context: The sentence contrasts his past ability with his current inability.
- Answer: could

7. Wong is bilingual; he _______ speak both English & Mandarin.
- Context: Being bilingual means having the ability to speak both languages.
- Answer: could

8. In 1960 people _______ search in Google.
- Context: Google did not exist in 1960, so people could not use it for searching.
- Answer: couldn't

9. Jane _______ see the church from her house 10 years ago now she can't due to tall buildings.
- Context: The sentence contrasts her past ability with her current inability.
- Answer: could

10. Bill _______ walk the entire stretch of Oxford street in 18 minutes today as it was empty.
- Context: The emptiness of the street made it possible for Bill to walk quickly.
- Answer: could

11. Gareth _______ watch the play as he was late by 30 minutes.
- Context: Being late by 30 minutes prevented him from watching the play.
- Answer: couldn't

12. Lisa _______ count the change fast as she was good in maths.
- Context: Her mathematical skills enabled her to count quickly.
- Answer: could

13. The giant _______ break the car but he didn't.
- Context: The giant had the physical strength to break the car, but chose not to.
- Answer: could

14. Anne _______ do backstrokes too as she learnt it from her new coach.
- Context: Learning from the coach gave her the ability to perform backstrokes.
- Answer: could

15. Chang and Wong _______ reach the MRT on time to catch the 9.55 train as they got delayed.
- Context: Being delayed meant they were unable to reach the MRT on time.
- Answer: couldn't

16. He _______ crash if he is not careful.
- Context: This is a conditional statement indicating a potential outcome if he is not careful.
- Answer: could

17. Jim _______ crush the ice as he didn't have a crusher.
- Context: Not having a crusher made it impossible for him to crush the ice.
- Answer: couldn't

18. It _______ be fun if all of us play together.
- Context: This expresses a hypothetical possibility.
- Answer: could

19. I _______ be wrong, as I have not read that book completely.
- Context: The incomplete reading makes it possible for the speaker to be wrong.
- Answer: could

20. Jimmy _______ sleep well last night due to thunderstorms.
- Context: Thunderstorms disrupted his sleep, making it impossible for him to sleep well.
- Answer: couldn't

Final Answers:

1. could
2. could
3. could
4. couldn't
5. could
6. could
7. could
8. couldn't
9. could
10. could
11. couldn't
12. could
13. could
14. could
15. couldn't
16. could
17. couldn't
18. could
19. could
20. couldn't

Boxed Answer:
\[
\boxed{
\text{1. could, 2. could, 3. could, 4. couldn't, 5. could, 6. could, 7. could, 8. couldn't, 9. could, 10. could, 11. couldn't, 12. could, 13. could, 14. could, 15. couldn't, 16. could, 17. couldn't, 18. could, 19. could, 20. couldn't}
}
\]