* The timing of their arrival was opportune, as the meeting was about to start. (Meaning: It was a good time for them to arrive)
* She waited for an opportune moment to ask for a raise. (Meaning: She waited for the right time to ask)
* The storm presented an opportune moment to go exploring the abandoned house. (Meaning: The storm created a good opportunity to explore)
* It was not an opportune time to discuss the issue, given the current political climate. (Meaning: It was not a good time to discuss the issue)
Let me know if you'd like more examples or have a specific context in mind!