___by the___look on his son's face,he began to ask the details about the concert.

问题描述:

___by the___look on his son's face,he began to ask the details about the concert.
为什么选C.surprised;excited请解释第一个空,并把涉及到的知识点详细讲清楚

首先,看到介词by,表前面的动词要用被动语态.你可以把供我们选择的几个选项列举出来,或许我可以为你解释更详尽一些.