第21题: [单项选择]In a second hand bookshop, Billy came across a book which he thought was certainly a ______edition. A. rare B. scarce C. seldom D. hardly 参考答案:A 答案解析:本题考查形容词用法。rare“罕有的;稀罕的”;scarce“缺乏的,不足的”;seldom“很少”;hardly“几乎不”。句意为:在旧书书店,比利遇到了一本他认为确实是珍藏版的书。