A. whether B. if C. either D. weather
单项选择题A group of youngsters sat under the big tree（）
A. chatting and laughing B. chatted and laughed C. was chatting and laughing D. was chatted and laughed
单项选择题Not until the bell had rung（）the classroom in a hurry.
A. he came into B. did he come into C. he has come into D. has he come into
