Written test part(共100分) Ⅴ. 单项选择(每小题1分,共10分) 从A、B、C、D四个选项中选择可以填入空白处的最佳答案。 ( A )21. —Look! There is _______ “B” and _______ “S” on that notebook. —It must be Bella Swift's. Let's get it for her. A. a; an B. an; an C. an; a D. a; a ( B )22. Come and buy your sports shoes _______ our great sale. They are only thirty dollars _______ two pairs. A. at; at B. at; for C. for; at D. for; for