I learned _____ the city for a long time. [ ]

A. she has been to

B. she has gone to

C. she had been in

D. she had gone to

某桥梁工程，主梁浇筑完成后，在拆除满堂支架的过程中，发生支架局部倒塌伤人事故。

[问题]事故发生后应如何进行处理?