a momentous occasion的用法和样例：
- Gone was the usual frivolous eating and shopping scene in the courtyard, the lax socializing and easygoing mood. Everyone realized this was a momentous occasion.
- a momentous occasion;a momentous decision.
- a momentous occasion; a momentous decision.
- I'd like to speak to you for a moment.
- For a moment his life was in jeopardy.