would have had to和would have to的区别

Question

来源这一句（原文背景是讲述古代壁画，都画在不见天日的黑暗洞穴里）：You would have had to make a special trip into the cave to make the paintings,and a special trip to go see it,and each time you'd have to bring along torches to light your way.

注意，would have to在句中被缩写了。它们有何区别？以该句为例，这种区别造成意思表达上的何种区别？谢谢。

Answer 1

从语义上说，这两个表达方式都是表达说话人的判断。前一个的推断、猜想意味浓厚，因为年代久远的事，推断的把握不是很大，用would have had to更为合体；而后一句逻辑性很明显，自然就用would have to。要注意的是，这两个用法的“判断”含义都是在讲述过去事情的条件才有的。would have to 如果用在现在时中多是表示“建议”。