美 [ˈhæpən tu]
影响或涉及（某人或某物）作为事件或行动的结果：在某人或某物身上发生或影响，作为某个事件或行动的结果。
对（某人或某物）产生不好或有害的影响：对某人或某物产生不好或有害的影响。
... did 是do的过去式，此处它表示的是一种强调的语气。 upside down 倒置的，颠倒的 happen to 碰巧 ...
... 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 ...
... 事件偶然发生的事 happening 强调事情的偶然发生 happen to 发生、碰巧、偶然发生 happen ...
发生于；偶然发生
You don't happen to know his name, do you?
你不会碰巧知道他的名字吧？
Did you happen to see her leave last Wednesday?
上星期三你正好碰巧看见她离开？
Did you happen to be listening?
你碰巧在听吗？
However,because Hank's songs told of real-life troubles with such great emotion, something unusual began to happen to his music.
VOA : special.2009.11.22
Then there came to be questions about whether the scenes, the stories in the book, actually did happen to him.
于是问题出现了，书里的那些情节和故事是否真正在他身上发生过。
1945年后的美国小说课程节选 : 耶鲁公开课
Something I can measure and I can tabulate, and when I turn my dT knob here I know what's going to happen to the enthalpy.
----热容，我们可以用实验，测出热容并成表,当我知道这里的变量。
热力学与动力学课程节选 : 麻省理工公开课
Virginians wanted Brown punished quickly to show what would happen to anyone who tried to lead a Negro rebellion.
VOA : special.2009.07.02
The film is about all the bad things that happen to a common man for no apparent reason.
VOA : special.2010.03.01
It is not yet known what will happen to HMV's branches and 4, 350 staff.
"It blew my mind to think this could happen to someone like me, " Grant said.
Every place has its risks, and here they happen to fall from the sky.