托福高手請幫忙 文法結構的選擇題

Question

_______ found in forests can possess deadly toxicity is an element of folk knowledge that has not been passed down to today's general public.

1. Those certain mushrooms
2. That certain mushrooms
3. Despite it, certain are the mushrooms
4. Even though certain mushrooms

能否請各位高手替我解答, 回答時請附詳解, 讓我知道其他三個選項錯誤的地方在哪裡 謝謝

Answer 1

正確的句子是:
That [certain mushrooms found in forests can possess

deadly toxicity] is an element of folk knowledge [that
has not been passed down to today's general public].
That1 A is { B [ that2 C ]}.
第一個 that 是從屬連接詞, 引導一個名詞子句, 當主
詞. that 置於句首時不可省略.
動詞是 is.
an element of folk knowledge 是主詞補語.
第二個 that 為關係代名詞(代表 knowledge), 當主詞來
引導一個形容詞子句, 修飾 knowledge. (that不可省略)
本來更常用的句型應該是寫成:
It is an element of folk knowledge that has not been
passed down to today's general public that(可省略)
certain mushrooms found in forests can possess deadly
toxicity.
It is { B [that2 C] } that1 A.
但是兩個 that 引導的子句直接相連, 甚至把第二個 that 再省略, 容易造成閱讀及語意上的困擾, 故以原句的寫法較恰當.
XO大大分析得很好, 不過答案是 2.

Answer 2

_______ found in forests can possess deadly toxicity is an element of folk knowledge that has not been passed down to today's general public.

1. Those certain mushrooms
2. That certain mushrooms
3. Despite it, certain are the mushrooms
4. Even though certain mushrooms

從最後開始看

.....that has not been passed down to today's general public.

尚未傳下來給大眾的...

.....is an element of folk knowledge
....一個基本的民俗知識

...is an element of folk knowledge that has not been passed down to today's general public.
一個尚未傳下來給大眾的基本民俗知識

can possess deadly toxicity
具有足以致死的毒

found in forests
從森林裡發現

到這應該就可以看出答案是1. Those certain mushrooms

Those certain mushrooms found in forests can possess deadly toxicity
那些從森林裡發現的那類香菇具有足以致人於死的毒

整句話也可.拆成
It is an element of folk knowledge that those certain mushrooms found in forests can possess deadly toxicity.
The knowledge that has not been passed down to today's general public.

Answer 3

我覺得答案是1
因為句子裡面已經有動詞以及子句了,所以缺的是主詞
2. 較常看到it is that.... or That+子句+is, 很少看過That....is... that...
3. certain可當形容詞和名詞, 但在名詞的意思是:某幾個;某些[(+of)],所以不能當主詞+are
4.even though即使的用法就是要有兩個句子的配套,即使怎樣....也不會怎樣....
但我不確定答案是不是這個, 只是一我自己的判斷啦!因為文法要能夠百分百的對也不是件容易的事~~