✔ 最佳答案
There is no passive form for the verb happen so
what happen ......? (Right)
what's happen ......? (Wrong)
The accident was happened when the restaurant owner arrived at his shop at 11:00 pm. (Wrong)
The accident happened when the restaurant owner arrived at his shop at 11:00 pm. (Right)
2008-02-17 22:11:30 補充:
Some verbs do not have a passive form. Here are some examples: break out / resemble / flee / suit / get / survive /happen / take place / let / die / occur / disappear / pass away / escape / race /exist