Her mother does not ______ of her going to study in the United States alone.

A．admit

B．agree

C．prove

D．approve

传染病流行过程的基本条件（）.

A.病原体，人体和他们所处的环境

B.病原体，带菌动物，易感人群

C.传染源，传播途径，易感人群

D.传染源，传播途径

E.社会环节，自然环节