[化学論文のための英語講座] 第10回：現在完了形と過去完了形 Part2

(English version is here.)

前回に引き続き、現在完了形と過去完了形です。過去完了形は現在完了形と示す期間が違います。以下の例文で確認しましょう。

(1) Continuous wave NMR had been commonly used up until the development of digital computers and Fourier transform spectroscopy.
訳文：デジタルコンピュータやフーリエ変換分光法が開発されるまでは、連続波法NMRが一般的に使われていた。

この文では「had been」はデジタルコンピュータとフーリエ変換の開発前までのことを表します。こういう関係を明確に伝えるため過去完了形を用います。「Continuous wave NMR was commonly used」のような過去形も使えますが、時間軸は曖昧になります。

もう一例を見てみましょう。

(2) Prior to demonstrating that organozinc compounds could be nucleophilic coupling partners, Negishi had revealed that organoaluminium compounds could be effectively coupled with aryl halides in the presence of catalytic palladium.
訳文：根岸は、有機亜鉛化合物が求核的なカップリングパートナーになりうることを明らかにする前に、有機アルミニウム化合物がパラジウム触媒の存在下でハロゲン化アリールと効果的にカップリングすることを明らかにしていた。

下線部分「Prior to demonstrating」は過去の出来事ですが、「Negishi had revealed」の方がより昔なので過去完了形が適切です。しかし、下線部分がなければ、過去の出来事を強調した「Negishi revealed that」としても良いです。「Prior to demonstrating...Negishi revealed that...」の構造も文法的には間違いではありません。

次回は「時制のまとめ」です。

Present Perfect and Past Perfect Tenses

Continuing the previous discussion, the past perfect and present perfect tenses differ in time frame. Let us examine the example sentence below.

(1) Continuous wave NMR had been commonly used up until the development of digital computers and Fourier transform spectroscopy.

In this sentence, had been indicates a time prior to the development of digital computers and Fourier transform. The past perfect tense is used to clearly convey this relationship. The simple past, i.e. was commonly used, can also be used, but the time frame becomes less clear.

Let us look at another example.

(2) Prior to demonstrating that organozinc compounds could be nucleophilic coupling partners, Negishi had revealed that organoaluminium compounds could be effectively coupled with aryl halides in the presence of catalytic palladium.

Prior to demonstrating is a past time period, furthermore, Negishi had revealed refers to an even earlier period, thus, the past perfect tense is appropriate. However, if prior to demonstrating were not present, the past event could be emphasized using Negishi revealed that. The structure Prior to demonstrating...Negishi revealed would also be grammatically correct.

Next time, let's look back on what we have covered tenses.