Question

We first met on a train in 2010，but we both felt immediately that we ________ each other for years.

A．knew	B．have known
C．had known	D．know

Answer 1

C

根据题干所提供的信息，首先弄清说话者在谈论过去的事情，因此用过去时，排除B、D两项，然后考虑动词know在felt之前，即过去的过去，因此用过去完成时。