2020年6月30日 星期二

finite vs non-finite

天筆者想講一講英文的 clause structure,先看看以下一個例句:
The proposal, if accepted by the government, will mean significant changes to the education system.

有人問 ‘if accepted by the government’ 是一個怎麼樣的句子結構?為甚麼 if 後面不用加任何 subject 就可以連接 accepted

大多數人學英文的 clause應該都學過 main clause subordinate clause 別,例如 You can stay for the weekend if you like,這句的 main clause You can stay for the weekend,而 subordinate clause if you like

外,clause 還有一個很重要的分類,就是 finite clause non-finite clause,這個概念可以很複雜,但簡單一點來說,finite clause 必須含有一個帶有時態的動詞,稱為 finite verb,而 non-finite clause 所含的動詞則沒有時態,稱為 non-finite verb

再深入淺出一點,以動詞 be 為例,若它以 am, is, are, was, were 的形式出現,就是 finite verb,因為這些都能顯示時態;若它以 been being 的形式出現,就是 non-finite verb,因為單從 been being 兩個字形是看不出甚麼時態的。

回到上述的 clause,基本上所有 main clause 必定是 finite clause,因為 main clause 的動詞一定要顯示時態;至於 subordinate clause 則可以是 finite clause non-finite clause,舉個例子說明:

1. As I am the person in charge, I have to inform all the parties involved.
2. Being the person in charge, I have to inform all the parties involved.

上句的 main clause I have to inform all the parties involved,而 subordinate clause 則有兩種表達方式,一是以 finite clause 表示:As I am the person in charge‘am’ 是帶有時態的;二是以 non-finite clause 表示:Being the person in charge‘being’ 不能顯示時態

這種可以同時用 finite clause non-finite clause 的句型有一個準則,就是句子主語在邏輯上必定要同一個人或事物,如果上句寫成 Being the person in charge, my duty is to inform all the parties involved 就不對了,因為 being the person in charge 的主語一定要是 I 而不能是 my duty

兩句的意思沒有別,視乎你想怎樣表達,不過用 finite clause 一般較為累贅,要重複出現主語,程度略低且美感不足,所以轉寫 non-finite clause 會顯得較有深度,予人文筆流暢的感覺。

Non-finite clause 有幾種句式:
1. to-infinitive,例如:
She arrived early (in order) to get a good seat.
所有 to-infinitive 都是以動詞原型出現,其實就是 non-finite verb
2. present participle,例如:
Having experienced a lot of difficulties, he realized the importance of being patient.
3. past participle,例如:
Trained as a ballet dancer since young, she amazed the audience with her graceful movements.
4. subordinate conjunction
有些連接詞可以後接 non-finite clause,如 before, after, when, if, unless, though, although 等,例如:
The boy was found fully conscious, though injured.

現在重看本篇開頭的句子:
The proposal, if accepted by the government, will mean significant changes to the education system.
句中的 if accepted by the government 是一個 non-finite clause,本來的 finite clause if it is accepted by the government,只不過這個寫法有點累贅,所以把 it is 刪去,句子看上去便簡潔得多。