句子的类型和目的

Sentences come in a variety of shapes 和 lengths. Yet whatever their shapes 和 lengths (or types), all sentences serve one of only a few very basic purposes.

句子的类型
Sentence variety is not about mere novelty; it is about meaning. You can avoid boredom (你rs 和 你r readers') 和 choppiness by varying 你r sentence types. Longer, more complex sentences can increase the impact of a shorter, simpler sentence.

Every sentence is one of the following types.

• 简单的
• 复合
• 复杂的
• 复合/复杂

In order to vary 你r writing, 你 want to be able to construct sentences of each kind. 掌握这四种类型, 虽然, 你 really only need to master two things: independent 和 dependent clauses. This is because the four types of sentences are really only four different ways to combine independent 和 dependent clauses.

(Let's review: independent clauses are essentially simple, complete sentences. They can st和 alone or be combined with other independent clauses. Dependent clauses are unfinished 虽然ts that cannot st和 alone; they are a type of sentence fragment 和 must be joined to independent clauses. 有关更多信息，请参阅TIP Sheet 独立的 & 从属子句:协调 和 从属.)

简单句
A simple sentence is simple because it contains only one independent clause:

贾斯汀 dropped his Agricultural Economics class.

A simple sentence is not necessarily short or simple. It can be long 和 involved, with many parts 和 compound elements. But if there is only one independent clause, it is, nevertheless, a simple sentence. The following example has a single independent clause with a single subject (贾斯汀)和复合动词(一饮而尽, 吞下, 呻吟着, 决定):

贾斯汀一口气喝下了第四杯咖啡, 吞下 a Tylenol for his pounding headache, 呻吟着, 决定 he would have to drop his Agricultural Economics class.

并列句
When 你 join two simple sentences properly, 你 get a compound sentence. 相反, a compound sentence can be broken into two complete sentences, 每个都有自己的主语和动词. You can join simple sentences to create compound sentences either of two ways:

• 加上分号
• With a comma 和 coordinating conjunction (for,, nor, but, or, yet, so)

 For example, the following pairs of independent clauses can be joined either way:

首页r has Basic Plant Science on Mondays 和 Wednesdays; Environmental Horticulture conflicted with his schedule.

首页r has Basic Plant Science on Mondays 和 Wednesdays, but Environmental Horticulture conflicted with his schedule.

(Be aware that if 你 join two simple sentences 不当, 你 do not get a compound sentence; 你 get a 加添的, most likely either a comma splice or a fused sentence. 欲了解更多信息，请参阅提示表 逗号拼接和连句 和 独立的 & 从属子句:协调 & 从属.)

复句
A complex sentence is a sentence that contains both a dependent 和 an independent clause. 在下面的例子中, 两个分句都包含主语和动词, 但是从属从句有, 除了, 依存词 尽管. If 你 start the sentence with 依存词 (or subordinating conjunction), 在分句之间加逗号. 另一方面, if 你 start with the independent clause 和 place 依存词 in the middle of the sentence, 不要使用逗号:

Even 虽然 Eva took Turf Management just to fill out her schedule, 她发现它出乎意料地有趣.

Eva found Turf Management unexpectedly interesting 尽管 she took it just to fill out her schedule.

 (For more on subordinating conjunctions, see the TIP Sheet 独立的 & 从属子句:协调 & 从属.)

复合句
A compound-complex sentence combines at least two independent clauses 和 at least one dependent clause. The punctuation rules remain the same: the two simple sentences are joined by one of the two methods described above, the dependent clause is punctuated (or not) depending on whether it precedes or follows an independent clause. 在下面的例子中, the dependent-making word signaling the beginning of the dependent clause is 而:

首页r was already in class, Eva was in the lab 而 贾斯汀 was sleeping off his headache.

While 贾斯汀 was sleeping off his headache, 首页r was already in class, Eva was in the lab.

首页r was already in class 而 贾斯汀 slept off his headache; Eva was in the lab.

句子的目的
句子可以做不同的事情. The purpose of some sentences is to make statements. Declarative sentences make statements 和 end with periods:

I am planning to drop Agricultural Economics.

 The purpose of another sentence may be to pose a question. These interrogative sentences ask questions 和 end with question marks:

Have 你 taken any Agricultural Engineering classes?

Imperative sentences give comm和s or make dem和s or requests. 它们通常以句号结束. An imperative sentence often has as its subject an unstated "你" (giving to beginners in English grammar the appearance of lacking a subject altogether). The subject of each of the following four sentences is "你:"

请把你们的家庭作业交上来.

停止. 下降. 卷.

Exclamatory sentences convey strong emotion 和 end with exclamation marks; use them sparingly:

小心那条响尾蛇!