She_____her hairstyle in her hometown before she came to chongqing for a better job.

She_____her hairstyle in her hometown before she came to chongqing for a better job.
A had changed B changed C has changed D was changing
再答：由于change her hairstyle这一动作早于came to Chongqing,故可以用过去完成时态(表示过去的过去).
关于过去完成构成为：had +v.(p.p.)
1)表示先于过去即到过去某一时间为止已经完成或结束的动作或状态,表示“过去的过去”,只有和过去某时或动作相比较时才可用,句中常用by,before或when等词引导时间状语从句或状语从句.
如：By the end of last year we had built fire new buildings.
2)表示持续到过去某一时间的动作或状态,句中常和for,since,until等短语或从句连用,如：It had snowed for a week by last Tuesday