crop up to appear or happen, especially when it is not expected （尤指意外地）出現，發生
crop up phrasal verb (LDOCE) 1 if a problem crops up, it happens or appears suddenly and in an unexpected way [= arise] 2 if something such as a name or a subject crops up, it appears in something you read or hear [= come up]: Your name kept cropping up in conversation.
當朋友問我，最近在看什麼書？我說普魯斯特《追憶似水年華》
他可能會繼續問：為什麼？我就可以說：It keeps cropping up. 不斷地在不同的地方提及到，從《1Q84》到《The Uncommon Reader》
