Extend implies making something longer or larger.
* Example: "He extended his stay at the hotel for another week."
Continue implies carrying on without interruption.
* Example: "He continued to work on the project even after it became challenging."
Similarities:
* Both suggest something carries on beyond its initial point.
Differences:
* Extend focuses on quantity (length, size).
* Continue focuses on uninterrupted flow.
When they can be used interchangeably:
* Sometimes they can be used interchangeably when the context clearly implies continuation, and it doesn't matter if there's an increase in length or not.
Example: "She extended/continued her education by taking more courses."
In general:
* Extend implies a deliberate action to make something longer or larger.
* Continue implies an ongoing process.