The lowest courses of flint are blackest and rough hewn with large gallets in black mortar joints.

底层的燧石颜色最深，由大块碎石融入黑色砂浆做成。

youdao

Research of the nano carbon black cement mortar electrical and electrothermal properties.

研究了纳米炭黑水泥砂浆的导电性和电热特性。

youdao

Reports from the NRF (National Retail Federation) were far more glowing, including both brick and mortar and online over Black Friday and the weekend.

FORBES: Black Friday/Cyber Monday: How Is The Street Voting So Far?

An additional woe for brick and mortar retailers comes courtesy of online retail behemoth Amazon, who just announced that they will host a 2011 Black Friday sale.

FORBES: Only One Shopping Day Left 'Til Tomorrow