单项选择题
In those early days, the boy company's（）business was model railways and cars.
A. useful B. full C. easy D. core
单项选择题 She（）mail the package before the post office closes.
单项选择题 The seller was trying to sign a substantial order（）
单项选择题 They look forward to（）the new products soon.
单项选择题 The telephone line is（）busy at the moment.
单项选择题 The computerized doll（）the quality test.
