狀語從句
所謂狀語從句,是指用來說明主句行為(或狀態(tài))發(fā)生的時間、原因、條件、地點、目的、結果及方式等。
1) 時間狀語從句:記住以下連接詞的意思和重點:
(1)when / while / as (當…時侯)
注意:while除了做時間狀語的連接詞外,還解釋為"雖然…","而…".
例如:He is very diligent, while she is very lazy. (他很勤奮,而她卻很懶。)
(2)before (after) 在…之前(后)
(3)until / not until(直到)注意:not until放在句首時,往往要求倒裝(詳見"第七講")
(4)as soon as / once (一…就…)
(5)immediately / instantly / directly 原本是副詞,這里作連接詞,表示"一…就…",
例如: I knew I had made a mistake directly (或用immediately / as soon as) I had done it. (剛做完這件事,我就知道我做錯了。)
(6)the moment / each time / every time / next time / the first time / the instant / the year原本是名詞或副詞,這里作連接詞用。
(7)hardly (scarcely)…when… / no sooner…than…"一…就…"
注意:這是時間狀語考試的重點句型,一是不要把兩個句型中的when和than的搭配搞錯了,二是要用倒裝語序(詳見"第七講")。
例如:
Hardly had I sat down when the telephone rang. (我剛坐下,電話鈴就響了。)
重點:在時間(和條件)狀語中,用一般時代替將來時。
例如:
We'll start as soon as the leader ______. (領導一來就開始。)
A.comes B.is coming C.will come D.came
根據英語"時態(tài)一致性"原則,主句與從句的時態(tài)應一致,答案似乎應該是B或C,但是正確答案是A,因為在時間狀語中,用一般時代替將來時。將上句改為過去時,道理也一樣:
He said (that) we would start as soon as the leader _____.
A.came B.was coming C.would come D.comes
答案應為A
2) 條件狀語從句:分真實條件句和非真實條件句(虛擬語氣)
重點:在條件(時間)狀語中,用一般時代替將來時(可參見時間狀語從句例子)
虛擬語氣(見"第六講")
主要連接詞:
(1)if / unless (除非 = if not 如果不)
例如:
Children should not be taken into the room of a very sick person ______ there is some special reason for it.
A.except B. besides C. unless D.whereas
解題思路:根據上面說過的連接原則,這里必須是一個"連接詞",而A,B都是介詞,因此正確答案只能在C,D中選。"whereas"意為"而",故正確答案為C.(不應把兒童帶到重病人房間,除非有某種特殊原因。)
(2)provided / on condition that (跟句子) (如果…)知道這也是連接詞就可以了,一般說,當考題中出現這種詞時,應傾向選擇。
3) 原因狀語從句:
主要連接詞:because/ since / as
要點:不要把連接詞 because與介詞短語because of ( + 名詞或-ing形式) 相混淆;
不要把表示原因的since與表示時間的since"自從…"相混淆;
不要把表示原因的as與表示時間的as"隨著…"相混淆;
順便提一下, because表示直接"因果關系",而since, as 是對事實的說明,主句和從句之間并不一定具有"因果關系".
例如:
As you are already 18 years old, you should know what to do and what not to do. (你已經18歲了,應該知道什么該干什么不該干。)
這個句子用because連接就不太合適。好在軍隊職稱考試中并不要求作這種分辨。
…for 注意:一般只能放在主句后面,即主句 + for從句,例如:
He must have gone to bed, for it is too late. (他肯定已經睡了;現在已經很晚了。)—— 該句不能用because
now that / seeing that / considering that (由于…)
Seeing that this problem was settled, they proceeded to the next one.(鑒于這個問題已經解決,他們開始進行下一個問題。) n
…in that(在于…)一般放在主句后面,例如:
Humans are superior to animals in that they can use languages as a tool to communicate. (人比動物高等,因為人能以語言作為工具進行交際。)