____,his eyes fill with tears again.A.When asked B.On asking C.On_英语解答

____,his eyes fill with tears again.A.When asked B.On asking C.On being D.When he was asked.
为什么选D.详细一点

人气：455 ℃　时间：2020-01-28 09:17:10

解答

独立主格结构. 选A就变成 his eyes 被问了,B C在非谓语动词的形式上不对