单项选择题
A. Check the goods before you dispatch them. B. If you have not got the cheque, do not send out the goods. C. You can send out the goods only after you have checked them.
A. You must wear your evening dress. B. You don't have to wear evening dress, but you can if you like. C. Evening dress will make you look nice.
A. 2 hours. B. 3 hours. C. 5 hours.