单项选择题
A. were based on original stories B. were based on stories already familiar to the audience C. were a mixture of comedy and tragedy D. do not exist today
A. a mother giving birth in spring has less nutrition during her pregnancy B．a mother givens; birth in autumn eats more vitamins during the last stage of her pregnancy C．a baby born in spring receives no protection from infections D．a baby born in autumn is never subject to any infections
A. they had long lost heart in class performance B. they were absent from class too often C. they didn’t get on well with other students D. they were so much cut off from the rest of the class