“was/were going to +动词原形”或“was/were + 动词不定式完成式”可表示未能实现的过去将来时间的动作。
Last Sunday we were going to visit the Great Wall, but it rained.
上星期天我们本想去游览长城的,但却下雨了。(没有去成)
I was to have helped with the performance, but I got flu the day before.
我是打算帮忙演出的,但前天我感冒了。(没有帮上忙)