n.

1. 面包皮；干面包片；馅饼皮[C][U]
2. 硬外皮，外壳；冰面；雪壳[C][U]
3. 地壳[the S]
   The earth's crust is between 5 and 25 miles thick.

   地壳有五至二十五英里厚。

4. 【动】甲壳[C][U]
5. 【医】痂[C][U]
6. 【俚】厚颜，无礼[the S]
   He had the crust to ask to borrow my new car!

   他竟有脸向我借新汽车！

vt.

1. 用硬皮覆盖；在……上结硬皮
   Ice crusted the stream.

   小溪上结了一层冰。

vi.

1. 结成外壳；覆有硬皮
   The snow crusted over.

   雪结成一层冰。

n.

1. the tough outer part of a loaf of bread.
   ▸a hard, dry scrap of bread.
2. a hardened layer or coating on something soft.
   ▸a layer of pastry covering a pie.
3. the outermost layer of rock of which a planet consists, especially the part of the earth above the mantle.
4. a deposit of tartrates and other substances formed in wine aged in the bottle, especially port.
5. Brit. informal a living or livelihood:
   earning a crust.

v.