If you have taken our foundational course “Core Concepts of English,” you would know that complete clauses (with their own subjects and corresponding finite verbs) can be embedded in other complete clauses to form “layers” of clauses in sentences.
You would also know that these complete embedded clauses can play different roles within the structure of the “outer” clause that they are embedded in.
For example, so-called “noun clauses” play the a noun role within their outer clauses.
A non-student recently asked about a sentence he read in a newspaper article that contains a “noun clause”:
What frightened her most was the possibility of her father leaving.
最令她害怕的，是她父親有可能會離開
If he had an overall framework for English grammar in place, he could easily analyze the structure of this sentence, which consists of an outer clause and an embedded clause inside it:
[ [ What frightened her most ] was the possibility of her father leaving. ]
最令她害怕的，是她父親有可能會離開
We know that there are two complete clauses in this sentence because there are two finite verb forms -- “frightened” and “was.” Only complete clauses have finite verbs.
Indeed, there are two clauses here. There is an embedded clause [ what frightened her most ] within the structure of the outer clause [ …. was the possibility of her father leaving. ]
The embedded clause [ what frightened her most ] is what we would call a “noun clause” -- because it plays the role of a noun in the outer clause that it is embedded in.
Here, [ what frightened her the most ] is playing the role of the subject (a noun role) in the outer clause -- it is the subject of the finite verb is “was.”
The meaning expressed by this noun clause is equivalent to “the thing that frightened her the most” -- so the meaning of the entire sentence is the same as:
The thing that frightened her most was the possibility of her father leaving.
最令她害怕的東西，是她父親有可能會離開
So, within the original sentence, in the outer clause, the subject is the noun clause [ what frightened her the most ], and the finite verb is “was”:
[ [ What frightened her most ] was the possibility of her father leaving. ]
最令她害怕的，是她父親有可能會離開
Now, let’s briefly look at the internal structure of [ what frightened her the most. ]
Remember that a noun clause has the structure of a complete clause, so it also has its own internal subject and finite verb.
Here, the subject is “what” (one of the pronouns that forms noun clauses) -- representing a noun phrase like “the thing” -- and its corresponding finite verb is “frightened.” The meaning that the entire noun clause expresses is equivalent to “the thing that frightened her the most.”
This is a simple but good example of a noun clause in a sentence.
The point I am always trying to bring across in these emails is that, with an overall grammatical framework in place, you can analyze every sentence you encounter in daily life systematically and treat it as a learning resource for both consolidating your existing knowledge and learning new things.
If you want to start building this systematic grammatical framework to supercharge your English learning, this is a good time to check out our foundational course “Core Concepts of English” at its current price:
如果你上過我們的基礎課程《Core Concepts of English》，你就會知道，完整子句（即有自己的主語和對應限定動詞的子句）是可以嵌入（embed）在另一個完整子句裡面，組成有多於一個子句「層次」的句子的。
你也會知道，這些完整的嵌入子句（embedded clauses），可以在它們所嵌入的「外層」子句結構中，扮演不同的結構角色。
例如，所謂的「名詞子句」（noun clause），就是在外層子句裡扮演名詞角色的子句。
最近有一位未上我們課程的學生問到一句他在報章文章裡讀到、當中包含「名詞子句」的句子：
What frightened her most was the possibility of her father leaving.
最令她害怕的，是她父親有可能會離開
如果他本身已經建立好了英文文法的整體框架，他就可以很容易分析這個句子的結構。這個句子包含一個外層子句，以及一個嵌入在裡面的子句：
[ [ What frightened her most ] was the possibility of her father leaving. ]
最令她害怕的，是她父親有可能會離開
我們知道這個句子裡有兩個完整子句，因為這裡有兩個限定動詞字形 —— 「frightened」和「was」。只有完整子句才會有限定動詞的。
的確，這裡句子包含兩個子句。有一個嵌入子句 [ what frightened her most ]，嵌入在外層子句 [ …. was the possibility of her father leaving. ] 的結構裡。
這個嵌入子句 [ what frightened her most ]，就是我們所說的「名詞子句」—— 因為它在自己所嵌入的外層子句裡，擔當的是名詞角色。
在這裡，[ what frightened her most ] 在外層子句裡擔當的是主語這個名詞角色 —— 它是外層的限定動詞「was」的主語。
這個名詞子句所表達的意思，相當於 「the thing that frightened her the most（最令她害怕的東西）」，所以整個句子的意思也就等同於：
The thing that frightened her most was the possibility of her father leaving.
最令她害怕的東西，是她父親有可能會離開
所以，在原本那個句子裡，在外層子句中，主語是名詞子句 [ what frightened her most ]，而限定動詞是 「was」：
[ [ What frightened her most ] was the possibility of her father leaving. ]
最令她害怕的，是她父親有可能會離開
現在，讓我們簡單看看名詞子句 [ what frightened her most ] 的內部結構。
記住，名詞子句本身有一個完整子句的結構，所以它也有自己的內部主語和限定動詞。
這裡主語是 「what」 （即其中一個可以組成名詞子句的代名詞）—— 它代替了 「the thing（XXX 的東西）」 這意思的名詞組 —— 而它對應的限定動詞就是 「frightened」。整個名詞子句所表達的意思，相當於 「the thing that frightened her the most（最令她害怕的東西）」。
這是一個簡單但很好的名詞子句例子。
我在這些電郵裡一直想帶出的一個重點，就是：只要你有整體文法框架，你就可以把日常生活中遇到的每一個句子，都用有系統的方式分析，並且把它當成一種學習資源，一方面鞏固自己已有的知識，一方面學習新的東西。
如果你也想開始建立這個系統性的文法框架，大大提升自己的英文學習效果，現在就是一個好時機，以目前價格了解一下我們的基礎課程《Core Concepts of English》：