1.let go of 放手
You can't let go of your friends.
你没能让你朋友放手。

2.be immersed in 陷于，沉浸于
I was so incompetent. I can't do anything well, but only to be immersed in fairy tales like dreams, without any disturbing.
我太无能了。什么事都做不好，只能沉浸在童话甜美的梦境里，任谁都不许吵醒我。

3.derive from 源自
Many later advice manuals derive from it.
后来的许多建议手册都起源于此。