题目

    When children start kindergarten,evident gaps in science knowledge already exist between Whites and minorities and between youngsters from upper-income and low-income families.And they often deepen into significant achievement gaps by the end of eighth grade if they are not dealt with during elementary school.     The findings suggest that,in order tor the United States to maintain long-term scientific and economic competitiveness in the world,policymakers need to renew efforts to ensure access to high-quality,early learning experiences in childcare settings,preschools and elem Only those who follow their dreams _______ achieve the final success． [　　] A．do they B．can they C．they can D．can