少年老成
to have an old head on young shoulders
少不更事
wet behind the ears：Although she is 20, she was still wet behind the ears in some ways.
天无绝人之路
God tempers the wind to the shorn lamb. /When one door shuts another opens.
天下乌鸦一般黑
Crows are black all over the world.
天助自助者
Heaven helps those who help themselves.
天有不测风云，人有旦夕祸福
It is the unexpected that always happens.
天衣无缝
These two ideas just fit like a glove.
天涯海角
ends of the earth：I'll find him to the ends of the earth. (out-of-the-way places; the uttermost part of the earth)
天经地义
a matter of course：It's a matter of course to respect our elders. (a universal truth; it goes without saying that...)
毛遂自荐
to recommend one's own person
小Car笔记：
shorn lamb：已剪过毛的羔羊
crow：乌鸦
all over the world：全世界