题目

Jane used to __________ to school, but not she is used to __________ a bike to school.    A. walk, riding                    B. walking, ride      C. walking, riding      D. walk, ride 答案：A基因型为AaBb的水稻自交,自交后代中两对基因都是纯合的个体占总数的A．B．C．D．