to crop up 突然出现（非正式）
英文释义
(INFORMAL) To occur suddenly and unexpectedly. (Note: often describing the appearance of problems).
例句
My new house looked fine until it started raining yesterday and a dozen leaks in its roof cropped up.
我的新房子看上去一直挺好，直到昨天开始下雨，屋顶突然出现了十几道裂缝。