When I finally got up to leave, we both knew that a real friendship between us
A. have formed
B. will form
C. is to form
D. was to form
网友回答
A. have formed
B. will form
C. is to form
(答案→)D. was to form
解析：主句中的谓语knew用的过去式，从句也要用相应的过去时态，排除A、B、C。只有D项是过去时态，故选D。