高一英语名词性从句.If you know __ it was that write A Tale of Two Cit

高一英语名词性从句
.If you know __ it was that write A Tale of Two Cities ,raise your hand.
A.who B.whom
(为什么不选whom)
2.In some countries ,___ are called public schools are not owned by the state.
A.what B.which
(为什么不选which）
3.Thinking ___ you know __ in fact you don't is a terrible mistake.
A.that that B.what what C.that what D.what what
(能否划分一下句子结构）

1.由于被强调部分是主语,所以要用主格；
2.主语从句中缺少成分,而which表示的意思是“哪一个”,这和语境不符；what are called public schools”的意思是：被称作公办学校的学校；
3.第一个空是宾语从句,用that引导；第二个空也是宾语从句,但是从句中缺少宾语,故用what引导.整个句子的意思是：认为你知道事实上你不知道的东西是个可怕的错误.