问题补充：
Mother asked the youngest kid with his toy car.
A. what the matter is
B. what is the matter
C. what the matter was
D. what was the matter
答案：
A. what the matter is
B. what is the matter
C. what the matter was
(答案→)D. what was the matter
解析：此处选出的应该是宾语从句，要用陈述句语序，根据前文asked可知用一般过去时。所以选D。句意：妈妈问那个年纪最小的孩子，他的玩具出了什么问题。选D。
