单项选择题
A. about doing B. to do C. doing D. do
In those early days, the boy company's（）bus...
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
She（）mail the package before the post offic...
单项选择题She（）mail the package before the post office closes.
A. has B. have to C. has to D. must to
The seller was trying to sign a substanti...
单项选择题The seller was trying to sign a substantial order（）
A. that is made with certain conditions. B. that you have finalized the delivery dates. C. then he could get a large discount. D. to be more flexible over terms of payment.
