1. This was a great lesson to me, and now I saw, though too late, the folly of beginning a work before we count the cost, and before we judge rightly of our own strength to go through with it.
    这事给了我很大教训。尽管为时太晚，我现在明白了：在开始做一件事之前，不先估计一下代价，不先正确地估计自己是否有做完这件事的力量，那真是太愚蠢了！

2. My folly has cost me dearly.
    我的愚蠢使我损失惨重。