单项选择题
Mr Green went home（）Christmas, the children had a good time（）Christmas Eve.
A. on, on B. at, on C. in, in D. at, at
单项选择题 --The boy is Telling a lie. --How do you know --His face has given him（）
单项选择题 At the moment the machine（）at full speed.
单项选择题 Seldom（）my boss in such a good mood since I came to work in this company.
