1.I suppose the reason is that we know all the circumstances that have occasioned them and so manage to excuse in ourselves what we cannot excuse in others.

【参考译文】我想，其原因应该是我们知晓一切导致自己犯错的情况，因此能够设法谅解自己的错误，而别人的错误却不能谅解。

【结构解析】suppose意思是“推想、料想”，"them"指上文中的“our own offenses ”，occasion在这里做动词，是“致使,惹起,引起”的意思。

2.how scornful we are when we catch someone out telling a lie; but who can say that he has never told not one, but a hundred?

【参考译文】当觉察到别人说谎时，我们是多么地蔑视他啊！但是，谁能够说自从未说过谎？可能还不止一百次呢。

【结构解析】catch sb. doing sth.意思是“撞见某人做某事”。

3.For my part, I do not think I am any better or any worse than most people, but I know that if I set down every action in my life and every thought that has crossed my mind, the world would consider me a monster of depravity.

【参考译文】至于我自己，我认为自己并不比大多数人更好或者更差，但是我知道，假如我记下我生命中每一次举动和每一个掠过我脑海的想法的话，世界就会将我视为一个邪恶的怪物。

【结构解析】for sb's part意思是“就某人来说”，set down意思是“写下，记下”，cross one's mind 是“无意中想到、偶然想起”，区别于经过思索才得到的想法。主语经常是 idea，thought，possiblity，比如：The thought of escape crossed my mind but immediately I dismissed it as being unrealistic. 逃跑的念头一闪而过，但我立刻打消了这一念头，因为太不现实。How did that fantastic idea cross your mind? 你是怎么想到那个妙计的？