They walked for miles on an empty road _____ their car had broken down.Options though in as due to

To fill in the blank in the sentence "They walked for miles on an empty road _____ their car had broken down," we need to choose the option that best connects the two parts of the sentence.

The options provided are: though, in, as, due to.

Analyzing the Options

1. Though: This word suggests contrast, but doesn't fit here as it doesn’t explain the reason for walking.
2. In: This doesn't make grammatical sense in this context.
3. As: This implies a cause-and-effect relationship and could fit well, making the sentence read smoothly.
4. Due to: This could also fit, indicating that their walking was a consequence of the car breaking down.

Conclusion

The best options to fill the blank while maintaining the meaning of the sentence and ensuring grammatical correctness are "as" and "due to." However, "due to" would typically require a rephrasing of the initial sentence structure.

Final Answer

The sentence can be completed with "as": "They walked for miles on an empty road as their car had broken down."