牢度的英文：
fastness

With the newly developed hairdye, you may only dye your hair once to make it look natural in colour for a long time.
染发品中新成就，一次成色，染发逼真，牢度持久。

This special treatment gives the thread added strength as well as creating a permanent sheen.
这种特殊的处理方法加强了纱线的牢度并使纱线产生永久的光泽。

The final choice would depend on fabric thickness, type of garment and required seam strength.
最终选用什么线应根据面料的厚度、服装的款式以及线缝所要求的牢度而定。

This is a fast delivery.
这是一个快投球。

You cannot react fast enough to just be a fast follower.
只做一个快速跟进者不能保证反应得足够快。

He runs as fast as Paul.
他跑得和保罗一样快。

Run as fast as you can.
你能跑多快就跑多快。

Why, I was fast asleep.
怎么，我睡得很熟的呀。