We first met on a train in 2000．We both felt immediately that we _____ each other for years.

A．knew

B．have known

C．had known

D．know

常见的井下工程事故有：卡钻事故；钻具事故；钻头事故；落物事故；（）；顿钻事故；卡电缆、卡仪器事故。