That's ----you've made a mistake. A.where B.what C.how D.whi

名词性从句,最忌讳用中文来套用连词.解题思路是先结构后意思.首先这是一个表语从句,具备使用后面各个连词的资格,第二,就是最主要的,要分析从句的成分.you have made a mistake,主谓宾都不缺,那就不能使用联系代词what,如果从句中缺宾语,you have made,那就只能用what,最后一步,看意思,用连词how.
补充说明,what既做连词,还充当成分,how 之作连词,不做成分如 I don't know how to do it
和i don't know waht to do