itself

1. The discussion resolved itself into a pleasant chat.
   讨论变成了愉快的闲聊。
2. The snake coiled itself around the tree.
   蛇盘绕在树上。
3. The tension soon transmitted itself to all the members of the crowd.
   这种紧张情绪很快感染了人群中所有的人。
4. The house itself is not particularly to my mind, but I like its environment.
   这房子本身并不特别合我的心意，但我喜欢它周围的环境。
5. The cat is washing itself.
   猫正在给自己洗脸。
6. The government made itself unpopular.
   这届政府使得自己失去人心。

it.self

pron.（代词）
That one identical with it:
它自己，它本身：和它相同的人或事
Used reflexively as the direct or indirect object of a verb or the object of a preposition:
反指自己：反身地用作动词的直接宾语或间接宾语或介词宾语：
例句：
The cat scratched itself.
猫自己抓痒

Used for emphasis:
自身，本身：用来强调：
例句：
The trouble is in the machine itself.
问题就出在机器本身

Used in an absolute construction:
用于独立的结构中：
例句：
Itself no great poem, it still reveals talent.
尽管不是伟大的诗歌，但它仍展露了诗人的天赋

Its normal or healthy condition or state:
正常的状态：事物普通的或健康的状态或情况：
例句：
The car is acting itself again since we changed the oil.
我们给车换过油后，它又可以发动了