----- Do you see why he hasn't turned up yet?----- Sorry, I don't know _______.
A、what the matter is
B、how matters stood
C、what is the matter
D、how is the matter
【正确答案】：C
【题目解析】：这个句子里，句子主语是what,而不是the matter，这是个疑问句，但是语序确跟陈述句的一样，是主语+系动词+表语。I don’t know 后的宾语从句中，what is the matter 仍然是个陈述句语序。
