单选题 He claims to be an expert in astronomy, but in actual fact he is quite ignorant on the subject. ______ he knows about it is out of date and inaccurate.
A. What little B. So much C. How much D. So little

【正确答案】 A
【答案解析】他自称是天文学专家，但事实上他对此学科基本一无所知，一知半解的了解也早已过时且不准确。考查名词性从句。what引导名词性从句作句子的主语，连接代词what修饰little，做know的宾语。