crop up
US /krɑːp ʌp/
UK /krɑːp ʌp/

1.
出現, 發生, 冒出
appear, happen, or come to attention unexpectedly
:
•
Problems always seem to crop up when you least expect them.
問題總是在你最不經意的時候出現。
•
A few interesting points cropped up during the discussion.
討論中出現了一些有趣的觀點。