It so happened that both of them were there. 赶巧他们两人都在那儿。
I got this book by chance at a second-hand bookshop. 我赶巧在一家旧书店里买到这本书。
牛津高阶第八版
美国韦氏词典
Dictionary.com
Free Dictionary
维基百科 (自由的百科全书)