adv.1. 快；迅速地to run fast快跑
These beautiful birds are fast disappearing.这些美丽的飞鸟正很快面临灭种。
The children are learning very fast.孩子们学得很快。
2. 紧；牢He made the wire fast to the metal ring.他把这根铁丝紧系在金属圈上。
When they arrived there, they found that the church door was fast shut.他们到达教堂时发现教堂门紧闭着。
to stick fast牢牢粘住
The boat stuck fast in the mud.船被牢牢地阻在泥塘里。