[化学論文のための英語講座] 第2回：受動態 Part1

(English version is here.)

研究論文で実験操作や結果を記載するときには、動作の主より結果を強調する時が多いので、主語に人称名詞は使わず、受動態を頻繁に使います。
英語の受動態は「主語＋be動詞＋動詞の過去分詞」形で、「される（された）」という受け身の意味を示します。この場合は動詞の過去分詞は形容詞の役割を持っていると考えられます。
受動態は現在形も過去形もあり、適切に使わないと違和感が起きる恐れがあります。

例文を見てみましょう。

(1) The mixture was cooled to -78 °C.
冷却された　（過去）

(2) The mixture is cooled to -78 °C prior to addition of alkyllithium.
冷却される　（一般に、いつも）

(3) The ions are drawn toward the path of the electron.
引かれる　（いつもの現象、複数形）

(4) The intermediate was found to epimerize readily.
エピマー化することがわかった　（過去、結果）

2回目に続きます。

Passive voice

The passive voice will be presented in two parts.

In research papers, when describing experimental procedures and results, the passive voice is often utilized because the results are often emphasized rather than the actor. The author is not the emphasis, so rather than using personal pronouns, the passive voice is often used.
As the readers know, in English the passive voice takes the form [noun + be verb + past participle]. In this case, the past participle can be thought of as taking an adjective role.
The passive voice has both present and past forms, and can seem awkward if not used appropriately.

Let us look at some example sentences.

(1) The mixture was cooled to -78 °C.
This is a past event.

(2) The mixture is cooled to -78 °C prior to addition of alkyllithium.
This is a general occurrence, and thus, the present is used.

(3) The ions are drawn toward the path of the electron.
This is an ongoing phenomenon and plural so the present is used.

(4) The intermediate was found to epimerize readily.
This is a past event.

To be continued in part two.