---Did the actor live alone in the house?

---Yes. He has a wife and two children. But ____ of them live with him.

A．none

B．all

C．both

D．no one

生态学发展大致经历了生态学的萌芽时期、建立时期、巩固时期和( )。

A．生物学时期

B．环境科学时期

C．现代生态学时期

D．现代生物学时期