• vi. 发生；碰巧；偶然遇到

hap,发生，运气，机会，词源同happy.即好运发生，后用于中性词即可指发生的好运也可指坏运。

happen

happen: [14] Surprisingly for such a common verb, happen is a comparatively recent addition to the English language. Old English had a number of verbs denoting ‘occurrence’, all long since defunct, including gelimpan and gescēon, and in the 13th century befall began to be used for ‘happen’, but the first signs we see of the coming of happen are when English acquired the noun hap ‘chance, luck’ in the 13th century.

It was borrowed from Old Norse happ, a word of uncertain ancestry but probably related to Old Slavic kobu ‘fate’ and Old Irish cob ‘victory’, and represented in Old English by gehæp ‘fit’. In the 14th century it began to be used as a verb meaning ‘happen by chance’, and hence simply ‘happen’, and before the century was very old it had been extended with the verbal suffix -en to happen.
=> happy, perhaps

happen (v.)

late 14c., happenen, "to come to pass, occur, come about, be the case," literally "occur by hap, have the (good or bad) fortune (to do, be, etc.);" extension (with verb-formative -n) of the more common hap (v.). Old English used gelimpan, gesceon, and Middle English also had befall. In Middle English fel it hap meant "it happened." Related: Happened; happening. Phrase happens to be as an assertive way to say "is" is from 1707.

1. Remember, keep a positive attitude and good things will happen.

记住：保持乐观的心态，好事自然会发生。

来自美剧《摩登家庭》

2. Do not wait for good things to happen to you. You need to walk towards happiness.

不要等待好事降临，你要向幸福进发。

来自金山词霸 每日一句

3. This is such an unforeseeable situation that anything could happen.

这种情况很难预测，什么事都有可能发生。

来自柯林斯例句

4. I go all tingly when I think of what might happen.

我一想到可能发生的事就满心欢喜。

来自柯林斯例句

5. He couldn't help worrying obsessively about what would happen.

他禁不住时刻担心将会发生的事情。

来自柯林斯例句