用 come about, happen, take place, break

问题：

用 come about, happen, take place, break out, occur 的正确形式填空.

① I was out of town at the time, .so I don't know exactly how it _________ .  

②The meeting _________ at 8:00 as planned.  

③It ________  to rain that morning.  

④A fire  ________     in the hotel last night.  

⑤It suddenly ________ to me that I had left my key in the office.