irony, satire,sarcasm究竟有何不同？

先看一下英文解释
irony : 1) the amusing or strange aspect of a situation that is very different from what you expect
2) the use of words that say the opposite of what you really mean,often as a joke and with a tone of voice that shows this

satire : a way of criticizing a person ,an idea or an institution in which you use humour to show their faults or weaknesses

sarcasm : a way of using words that are the opposite of what you mean in order to be unpleasant to sb or to make fun of them
可见 irony 和 sarcasm 都有反语的意思 而 sarcasm通常指对人进行
挖苦嘲讽，irony可以指其他事物。
satire和上面两个有区别，是指通过幽默对人，想法或机构的讽刺和取笑
比如讽刺社会的阴暗面等。

satire，用幽默或夸张的手法表现某个人的愚蠢行为
sarcasm，一种写法或讲演，表面上说的是这个，其实说的是相反的一面，经常带有侮辱的意思
irony，一种微妙的幽默，说的东西并不是真正想说的