bulk 和mass有何区别？

bulk
巨大;庞然大物;大块（体积,容积大）
(巨大的)物体；(尤指肥硕的)身躯
大批，大量 ，大团，大块
mass
(聚成一体的)团，块，堆，群，片（体积,容积比bulk 小）
一大片，块面，大量，众多

bulk
例：
The truck pulled out of the lot, its bulk unnerving against the dawn.
拂晓时分，卡车驶出了停车场，庞大的车身看起来有点儿可怕。
Bannol lowered his bulk carefully into the chair.
班诺尔那肥硕的身躯小心地坐落到了椅子上。
Buying in bulk is more economical than shopping for small quantities.
大批采购比少量购买更经济实惠。

mass
On his desk is a mass of books and papers.
在他书桌上有大堆的书和文件。
There's masses of work for her to do.
她有一大堆的工作去做。
She had a mass of auburn hair.
她有一头浓密的棕发。
...before it cools and sets into a solid mass.
…在它冷却成为一块固体之前。