选项A that除了 引导定语从句 能作代词 外 引导其他从句 不能作 句子成分 故错
选项B不能引导 状语从句 故错
选项C是正确答案 这是介词短语 作状语 what从句 作介词宾语
选项D though是连词 后面不能跟宾语
In spite of what has recently been done to improve the conditions of elementary schools ,a great number of children are unable to go to school.
句子分析In spite of what has recently been done to improve the conditions of elementary schools 是介词短语作 让步状语
其中In spite of是短语介词 后面是名词性从句 作短语介词 的宾语
what是连接代词 引导名词性从句 并作从句中的主语
has recently been done 是从句中的 谓语
to improve the conditions of elementary schools是从句中的状语 ,
a great number of children是主语
are unable to go to school是谓语
句子意思 尽管最近已经为改善小学条件采取了措施,但很多孩子依旧不能上学.