自2010年至今的四级考试中， 共出现过 次
自2010年至今的六级考试中， 共出现过 次
VERB （偶然）发生，出现 Something that happens occurs or is done without being planned.
We cannot say for sure what will happen...
The accident happened close to Martha's Vineyard.
VERB （作为结果）发生，产生 If something happens, it occurs as a result of a situation or course of action.
She wondered what would happen if her parents found her...
He trotted to the truck and switched on the ignition. Nothing happened.
VERB （尤指不愉快的事）发生（在…身上）;(某人)遭到;遇到 When something, especially something unpleasant, happens to you, it takes place and affects you.
If we had been spotted at that point, I don't know what would have happened to us...
It's the best thing that ever happened to me.
VERB 碰巧;凑巧 If you happen to do something, you do it by chance. If it happens that something is the case, it occurs by chance.
We happened to discover we had a friend in common...
I looked in the nearest paper, which happened to be the Daily Mail...
PHRASE 碰巧，恰恰（尤引出令人意外的事） You use as it happens in order to introduce a statement, especially one that is rather surprising.
She called Amy to see if she had any idea of her son's whereabouts. As it happened, Amy had.