The local government should __ the respon-sibility to provide those poor children with equal

opportunities to receive education.     [ ]

A. give                    

B. offer    

C. draw                    

D. undertake

咖啡因在苯甲酸钠的存在下溶解度由1：50增至1：1.2，苯甲酸钠的作用是

A．助溶

B．防腐

C．抗氧化

D．止痛

E．增溶