fast既是形容词,也是副词.形容词 a.1.快的;迅速的;速度快的He is a fast reader.他读书速度很快.2.完成得快的He did a fast job.他很快就干完了.3.牢的;紧的;稳固的He kept a fast hold on the rope.他紧紧抓牢绳子....