句子的基本觀念
(1). 句子的種類：句子可以簡單地分為獨立子句與從屬子句。獨立子句是可以單獨存在的，而從屬子句是由從屬連接詞如 although, though, because, when, while, since, if, unless 所引導的句子，這類句子是不能單獨存在，要依靠在獨立子句之中的。
例：Although they are poor. (本句為從屬子句，不單獨存在)
They are generous. (本句為獨立子句，屬於S+ VP的簡單句)
Although they are poor, they are generous. (=They are generous although they are poor.) [本句亦為獨立子句，由主要子句“they are generous”與從屬子句“although they are poor”所構成，這種結構稱為複合句。]
請再思索下列各句的特牲：
1. When the telephone was invented by Bell. (本句不成立)
2. Bell invented the telephone. (本句為獨立子句，屬簡單句)
3. When he comes, I will tell him the details. (本句為獨立子句，屬複合句)
4. Don’t make so much noise because the baby is sleeping. (本句亦為獨立的複合句)
註：由原形動詞片詞所形成的結構，如“Turn off the radio.”“Please come back as soon as possible.”“Don’t tell him the news.”皆屬於簡單式的獨立子句。
(2). 主詞與動詞：主詞與動詞為任何子句不可缺少的兩大基本元素。可以當主詞
的結構為名詞片詞、主格代名詞或所有格+名詞、不定詞或動名詞、名詞子句(由that或when, where, what, why, how, whether所引導的子句)
請思考下列句子主詞為何種結構：
1. Many people came to the meeting yesterday. (名詞片語)
2. When he came home, his parents were having dinner. (主格代名詞及所有格加名詞)
3. To finish the work in two days is impossible. (不定詞片語)
4. Collecting stamps is a good hobby. (動名詞)
5. Whether you go or stay is not my business. (名詞子句)
6. Why he killed himself is still a puzzle to all of us. (名詞子句)
7. That honesty is the best policy is an obvious fact. (名詞子句)
請注意：不定詞或動名詞當主詞是指整個動作，而名詞子句是指整件事情，故動詞皆要使用單數。
在動詞的使用上要特別注意幾項重點，即單複數、時態、及主動或被動。請思考下列句子動詞錯在那裡：
1. Helping others make them feel happy. (make改為makes)
2. What he wants are a new bicycle. (are改為is)
3. One of the big city’s problems are traffic congestion. (are改為is)
4. The explanation for these questions are very complicated. (are改為is)
請注意：在“名詞+介系詞+名詞+動詞”的結構中，主詞為第一個名詞，介系詞後面的名詞為受格，故動詞的單複數要與第一個名詞一致。
5. The meeting is first held in 1940. (將is改為was)
6. My father worked for that company since 1980. (將worked改為has worked)
7. The first highways built by the Romans. (改為were built)
8. His action was caused much concern to the Government. (改為caused)
另外，要特別注意一個主詞搭配一個動詞的觀念，假如有兩個動詞，則應(a)加對等連接詞and, or, but或(b)將其中一個動詞改為分詞，主動用現在分詞，被動用過去分詞。請思考下列各句：
1. He was sick took some medicine. (改為and took)
2. They have used the information gathering from various magazines. (gather“收集”與information搭配應為被動觀念，故改為gathered)
3. The man wore a coloured shirt was our English teacher. (wore“穿戴”為主動語態，故改為 wearing)
