I got caught in the traffic jam on the way,or I _here on time为何不用could have been,而用had been

问题描述:

I got caught in the traffic jam on the way,or I _here on time为何不用could have been,而用had been

应该填could/would/might have been,而不是had been.
本题考查虚拟语气中的含蓄条件句,or为“否则,要不然”的意思.