To fill in the blanks with the correct coordinators (FANBOYS: for, and, nor, but, or, yet, so), here are the answers along with explanations:

11. The shop was closed, **so** Dan couldn't get any butter.
*Explanation: "So" is used to show a cause-and-effect relationship.*

12. The sun was shining, **and** the birds were singing.
*Explanation: "And" is used to add related information.*

13. They didn't eat anything, **nor** did they drink anything.
*Explanation: "Nor" is used with negative constructs to indicate that neither of the two actions occurred.*

14. Linda's friends invited her to the cinema, **but** she didn't want to go.
*Explanation: "But" is used to contrast two opposing statements.*

15. Be quiet **and** sit down.
*Explanation: "And" is used to combine two commands or actions.*

### Answers Summary:
11. so
12. and
13. nor
14. but
15. and