单项选择题
A. after
B. when
C. if
D. unless
单项选择题 A:Good weekend? B:（）
单项选择题 Mr. McNeil asked Mr. Don Bradley to ship the goods（）air.
单项选择题 （）the Manager’s not available at the moment. But the Assistant Manager is here.How Can I help you, madam?
单项选择题 A:Welcome to Bibury Systems. B:（）
单项选择题 （）,three months ago I could not have negotiated this deal.