完形填空This morning as Jack and Istarted our walk,the strangest thing

happened
今早正当我和杰克开始我们的散步时,最最奇怪的事情发生了
happen
vi.发生
vi.The accident happened at six o'clock.
事故发生在六点钟.
vi.碰巧
vi.I happened to see her yesterday.
vi.我昨天碰巧见到她.
vi.出现
vi.I tremble at the thought of what may happen.
vi.我想到可能出现的情况就不寒而栗.
vi.偶遇
vi.I happened on just the thing I'd been looking for.
vi.我偶然发现了我一直在寻找的东西.
习惯用语
as it happens 碰巧来到,恰好出现
be likely to happen 可能要发生
if anything should happen to sb.如果某人发生什么意外[不幸]
happen along 恰好来了
happen in [美]偶然到...(来)
happen in with 偶然和...碰见
happen upon 碰巧碰上[发现]
happen on 碰巧碰上[发现]
happen to (和名词连用)临到...头上(某情况,尤指不幸的事); (和动词连用)偶然; 碰巧
happen what may 无论发生什么事,不管怎样
be what may 无论发生什么事,不管怎样
happen to say 偶然提到