He has been fired and will have to _______ charge of his office tomorrow.

A．take over

B．hand over

C．get over

D．go over

药物化学结构修饰的目的

A．提高药物对靶部位的选择性

B．提高药物的稳定性

C．延长药物作用时间

D．降低药物的毒副作用

E．提高药物与受体的结合