能給你的文章加分的英文分號與圓括號用法

分 號

分號 (semicolon)?可以認為是介于句號 (period)?和逗號 (comma)?之間的一種標點。它與句號的相同之處在于，兩者都是用來分隔兩個完整的句子——換句話說，分號前后的句子在語法上都應該是獨立完整的，中間不需要連詞，這一點與逗號不同。而它與句號的區別則在于，在文氣和邏輯上，分號并不像句號那樣有很強的分隔作用，這一點則于逗號接近。試對比下面三個句子：

Noble metals generally exhibit excellent catalytic performances, however, their applications are limited by the relatively low abundance and high cost.???

Noble metals generally exhibit excellent catalytic performances. However, their applications are limited by the relatively low abundance and high cost.???

Noble metals generally exhibit excellent catalytic performances; however, their applications are limited by the relatively low abundance and high cost.????

例句1中，兩個句子以逗號分隔開，兩句之間在邏輯上是轉折關系，但中間缺少連詞（注意，however是副詞而不是連詞），所以在語法上是錯誤的。

例句2中，兩個句子以句號分隔開，所以在語法上并無不妥 (grammatically correct) 。但從兩句之間的邏輯關系上來看，則顯得有些斷裂，即文氣不暢。另外從英文中多長句這一習慣來看，兩句之間用句號斷開也顯得有些碎片化。

例句3中，兩個句子以分號分隔開，既不像逗號一樣需要連詞，也不像句號一樣將文氣截斷——換句話說，既保證了語法上的正確性?(grammatical correctness)?，又保證兩個句子在邏輯上的連貫性?(logical continuity) ；同時兩句連綴成一個長句，也符合英文的表達習慣。

簡而言之，從語法上來說，任何一個分號都可以替換成句號；但從文氣上來講，分號更突顯前后兩句在邏輯上的「藕斷絲連」。下面按各種邏輯關系各舉幾例：

1. 并列關系（常與冒號配合使用）：

Matter can undergo two types of changes: chemical changes or reactions are changes in composition;?physical changes are changes in state or physical form and do not affect composition.

The four basic stages of the scientific method are: (1) XXX; (2) XXX; (3) XXX; (4) XXX.

2. 轉折關系：

All truths are easy to understand once they are discovered; the point is to discover them.

Gamma ray is not made up of particles;?rather it is electromagnetic radiation of extremely high penetrating power.

3. 遞進關系：

Astronomy's tools are not only diverse; they are also changing rapidly.

As designed, both space probes sent by NASA will not only detect Earth-like planets around nearby stars; they will also measure the planets’ physical and chemical characteristics.

4. 因果關系：

When a static positive charge builds up in one place, a negative charge of equal size appears somewhere else;?therefore, charge is balanced.

The outer planets move slowly and their orbits are very large;?thus they take a long time to go once around their orbit.

5. 對比關系：

Objects at rest stay at rest;?objects in motion stay in motion.

An ordinary microscope uses a beam of light to illuminate the object;?an electron microscope uses a beam of electrons.

6. 承接關系：

In the word photon, phot-?means light;?-on?signifies a particle.

Formic acid is injected by an ant when it bites;?this leads to the burning sensation that accompanies the bite.

7. 進一步釋義：

Mass and volume are extensive properties;?they depend on the amount of matter in a sample.

The properties of nonmetals are generally opposite those of metals;?for example, nonmetals are poor conductors of heat and electricity.

另外，如果分號隔開的句子之間在結構上相似，在用詞上重復，則可以將重復的部分適當省略，用逗號代替，這樣可以減少啰嗦冗余之感。試比較：

By 1994, astronomers had found only three exoplanets; by 2017, they had found about 3500.

By 1994, astronomers had found only three exoplanets; by 2017, about 3500.

Some telescopes are on mountaintops; others are in Earth orbit; yet others are in interplanetary space.

Some telescopes are on mountaintops; others, in Earth orbit; yet others, in interplanetary space.

由此可見，分號間隔的句子中將重復的內容 (紅色部分) 替換成逗號，可以讓語句變得簡潔緊湊。

圓 括 號

圓括號 (parentheses) 的作用是增加一些補充說明的信息，圓括號中的內容可能是一個單詞（甚至一個前綴/后綴），一個短語，或一個或幾個句子。

However, the conclusion was based on some (over)simplified assumptions. I would like to suggest?the authors?add some?(semi)quantitative?analysis results.

An oscillating (and therefore accelerating) electric charge causes a disturbance that moves outward through space as an electromagnetic wave.

Sirius, the brightest star in the sky, lies within the boundaries of the constellation Canis Major (meaning the “big dog”).

Nearly all short-period comets have prograde orbits; that is, they orbit the Sun in the same direction as the planets. (Comet Halley, with its retrograde orbit, is an exception.)

注意：圓括號中的內容必須在語法上是可有可無的。換句話說，如果把括號中的內容去掉，原句在語法上必須仍是正確的。試辨析：

The Sun (and its associated planets)?are located about halfway out from the center of the Milky Way Galaxy.???【主謂不一致】

The Sun (and its associated planets)?is located about halfway out from the center of the Milky Way Galaxy.??

The Sun and its associated planets?are located about halfway out from the center of the Milky Way Galaxy.??

科技論文要求論述嚴謹，而圓括號可以起到「打補丁」的作用，減少語義上的漏洞，讓表意更加精準且豐富。例如：

Salts of Group 1 cations (with some exceptions for Li+) are soluble.

For most materials (water ice being a rare exception), the solid form of the material is more compact than the liquid form.

With the speed of light, it will take us a bit over four years to cover the distance from Earth to the nearest star?(other than the Sun).

The European Union has funded two specific?flagship efforts, one in graphene (and other two-dimensional materials),?and the Human Brain Project, which seeks to simulate the human brain.

當然，引入補充說明的成分還可以借助逗號 (comma)或長劃線 (em dash)，但相比之下，圓括號的優點在于可以讓語句顯得更加緊湊、有層次而不至于瑣碎或喧賓奪主，有時還可以起到消除歧義的作用。試看下面幾例：

For more challenging reactions (such as toluene oxidation), no catalysts capable of high-efficiency and large-scale conversion have been reported.【此處若用逗號，會顯得有些碎片化】

Because the electric field points directly away from a positively charged particle (or directly toward a negatively charged particle), the force that a second charge feels is either directly toward or directly away from the first charged particle.【此處的圓括號使前半句更加緊湊，且降低了前半句的份量感；如果橙色部分不放到圓括號里，前半句會顯得有些啰嗦笨重，讓整個句子有「頭重腳輕」之感】

Human-made space probes have landed on Mars, Venus, Titan (Saturn’s largest moon), and an asteroid.【此處橙色部分為注釋說明成分，圓括號可使層次更加分明；若將圓括號改為逗號，則會產生歧義】

多說一句，在一些不太嚴肅的語境中，圓括號還很適合用來吐槽，提升幽默感。試體會：

Long before Columbus’s famous (or possibly infamous) journey to the New World, anyone who had read Aristotle or other Greek philosophers knew that Earth is a ball.【括號里的內容說明，哥倫布發現新大陸之旅是舉世聞名的，但在某種意義上也是臭名遠揚的】

After three weeks on set, the cast was fed up with his direction (or, rather, lack of direction).【括號里的內容說明，演員們都受夠了導演低水平的導戲，甚至認為那都不能叫「導戲」】