The helping verb have 2. Here, what's is the contraction of what has. 例句：there happened to be a telephone booth.
Helen Blair (Packet, 18961920) UWDC UWMadison Libraries
There happened to be是由there be句型演变过来的，仍是there be结构； it happened to be.，意思是：结果碰巧是.
What happened?和what's happening?的区别是什么？ what happen?表示发生了什么，用于询问发生了什么事情，通常用于过去的事件或突发情况。
What happened 和 what's happened两者的区别： 是问 what happened？只是想知道过去所发生的事情， 而如果用what's happened？则强调对现在的影响。，即想知道过去所发生的什么事. 接下来让我们看下what happen和what happened的用法区别： 1.词性：what happen是用原形动词happen构成的现在时短语，而what happened是用动词happen的过去式happened构成的过去. When describing an event in the past speech, should i use present or past tense for happen. 'happend' is a spelling mistake of happened.
The past participle of the main verb the.
