The nest box contained two chicks: just small grey balls of fluff.窝里有两只雏鸟：看上去还只是两个灰色的毛球。She noticed some bits of fluff on the sleeve of her sweater.她发现羊毛衫的袖口上起了一些毛球。I've only worn this jumper twice, and it's already begun to bobble.这件套衫我只穿了两次，却已经开始起毛球了。