单项选择题
A. This book can only be exported to Singapore. B. The book should get a license from Singapore before sale. C. This book is sold just in Singapor
A. you should send them a written notice. B. you can only make it at a specified period. C. you can contact them by phon
A. Every flight departs in the morning. B. Two flights go to the same country. C. All flights arrive in the afternoon.