[化学論文のための英語講座] 第69回：コロンとセミコロン

(English version is here.)

英語で最も一般な句読点はピリオドとコンマですが、コロンまたはセミコロンが必要な場合もあります。

I. コロン

コロンの役割の一つに、ある文節とそれに関連する列記や補足説明を分けるというものがあります。通常コロンの前方は完全文で一般的、後方は具体的です。例文を見てみましょう。

1. Three bases were investigated: triethyl amine, Hünig's base, and pyridine.
2. Several bases were tried: triethyl amine was the most effective.

例文１では、コロンは列記の前にあります。例文２では、コロンは補足説明の前にあります。

II. セミコロン

セミコロンの役割の一つに、関連する二つの文章をを繋げるというものがあります。つまり、等位接続詞の役割を果たします。この場合、セミコロンの使い方が正しいかどうかを確認するために、ピリオドまたは「and」をセミコロンの代わりに使います。結果が文法的に正しければ、セミコロンの使い方も正しいことになります。例文を見てみましょう。

3. UV-vis spectroscopy relies on electronic transitions; IR spectroscopy relies on molecular vibrations.
訳文：紫外可視分光法は電子遷移に依存し、赤外分光法は分子振動に依存する。

4. UV-vis spectroscopy relies on electronic transitions. IR spectroscopy relies on molecular vibrations.
訳文：紫外可視分光法は電子遷移に依存する。赤外分光法は分子振動に依存する。

5. UV-vis spectroscopy relies on electronic transitions and IR spectroscopy relies on molecular vibrations.
訳文：紫外可視分光法は電子遷移に、赤外分光法は分子振動に依存する。

セミコロンは前文と後文は関係があるのを暗示しますが、どのような関係かは明示しません。３〜５は文法的に正しく、大体同じですが例文３ではセミコロンが「しかし」という感じにさせます。例文４と５では、前文と後文の関係を明示しません。

コンマが多い複文がたまにあります。内容を整理しもっと読みやすい文を書くために、コンマ一個の代わりにセミコロンを使うことができます。例文をみてみましょう。

6. Ciguatoxins, cyclic polyethers found various marine organisms, understood to be of microbial origin, and responsible for ciguatera, a human food poisoning, are highly challenging synthetic targets, and attract attention from chemists due to their complex structures, biological activity, and social relevance.

コンマ一個をセミコロンにしましょう。

7. Ciguatoxins, cyclic polyethers found various marine organisms, understood to be of microbial origin, and responsible for ciguatera, a human food poisoning, are highly challenging synthetic targets; and attract attention from chemists due to their complex structures, biological activity, and social relevance.

例文が少し読みやすくなったと思いますが、これぐらい長い文章は二つにしたほうが良いかも知れません。

8. Ciguatoxins, cyclic polyethers found various marine organisms, understood to be of microbial origin, and responsible for ciguatera, a human food poisoning, are highly challenging synthetic targets. They attract attention from chemists due to their complex structures, biological activity, and social relevance.

次回はミニコーナーです。

Colon and Semicolon

The most basic punctuation marks in English are the period and the comma, but there are cases for which the colon or semicolon are necessary.

I. Colon

One of the roles of a colon is to separate a clause from a related list or a supplementary explanation. Usually, the portion preceding the colon is a complete sentence and is general, and the part following the colon is specific. Let us look at some example sentences.

1. Three bases were investigated: triethyl amine, Hünig's base, and pyridine.
2. Several bases were tried: triethyl amine was the most effective.

In sentence 1, the colon precedes a list. In sentence 2, the colon precedes a supplementary explanation.

II. Semicolon

One of the roles of a semicolon is to connect two related sentences. That is to say, it fulfills the role of a coordinating conjunction. In this case, in order to confirm whether a semicolon is used properly or not, the semicolon can be replaced with a period. If the result is grammatically correct, the semi-colon is used correctly. Let us look at some examples.

3. UV-vis spectroscopy relies on electronic transitions; IR spectroscopy relies on molecular vibrations.
4. UV-vis spectroscopy relies on electronic transitions. IR spectroscopy relies on molecular vibrations.
5. UV-vis spectroscopy relies on electronic transitions and IR spectroscopy relies on molecular vibrations.

A semicolon suggests that the joined sentences are related, but it does not reveal how. Sentences 3, 4 and 5 are correct and largely the same, but sentence 3 gives a feeling of contrast: the semicolon implies however. Examples 4 and 5 do not show a particular relationship between the two statements.

Compound sentences with many commas appear at times. To organise content and to write a more readable sentence, a semicolon can be used in place of a period. Let us look at an example.

6. Ciguatoxins, cyclic polyethers found various marine organisms, understood to be of microbial origin, and responsible for ciguatera, a human food poisoning, are highly challenging synthetic targets, and attract attention from chemists due to their complex structures, biological activity, and social relevance.

Let us replace a comma with a semicolon.

7. Ciguatoxins, cyclic polyethers found various marine organisms, understood to be of microbial origin, and responsible for ciguatera, a human food poisoning, are highly challenging synthetic targets; and attract attention from chemists due to their complex structures, biological activity, and social relevance.

The sentence has become a little easier to read, but with a sentence this long, it is probably better to form two sentences.

8. Ciguatoxins, cyclic polyethers found various marine organisms, understood to be of microbial origin, and responsible for ciguatera, a human food poisoning, are highly challenging synthetic targets. They attract attention from chemists due to their complex structures, biological activity, and social relevance.

At next time, we will post mini corner.