would be going to 是过去将来进行时，用来表示过去某个时间以后的的行为。
你可以分步判断
第一步：would + 动词原形 be 属于过去将来时
第二步：be + 现在分词 going 属于进行时
第三步：第一步的过去将来时 + 第二部的进行时 = 过去将来进行时
【例如】
He announced which two would be going. 宣布哪两个人会去。
He said the workers would be going back down the mines. 他说工人们会重回井下工作。
She was free for five whole days, from Christmas Eve. And so she would be going to Charles, to join her family. 她从圣诞夜开始有整整5天的自由时间，于是她准备去查尔斯跟家人呆在一起。