（『英語の文型と文法』
p.251）元の文：I studied English yesterday.
(1) Did you study English yesterday?
(2) Yes, I did. I studied English yesterday.
(3) Did you study mathematics yesterday?
(4) No, I didn't. I didn't study mathematics yesterday.
(5) What did you study yesterday?
(6) I studied English yesterday.
(3)〜(6)で置換の対象とされているのは、この例の場合は目的語（English/mathematics）だけであるが、実際には「元の文」の各要素について置換を試みることができる。例えば…
・Ｓについて：
(3) Did your father study English yesterday?
(4) No, he didn't. He didn't study English yesterday.
(5) Who studied English yesterday?
(6) I studied English yesterday.
・Ｖについて：
(3) Did you teach English yesterday?
(4) No, I didn't. I didn't teach English yesterday.
(5) What did you do yesterday?
(6) I studied English yesterday.
・Ｏについて：（上例のまま）
(3) Did you study mathematics yesterday?
(4) No, I didn't. I didn't study mathematics yesterday.
(5) What did you study yesterday?
(6) I studied English yesterday.
・Ｍについて：
(3) Did you study English the day before yesterday?
(4) No, I didn't. I didn't study English the day before yesterday.
(5) When did you study English?
(6) I studied English yesterday.
といった具合である。
なお、上では１つの要素をまるごと置換する場合だけを考えたが、“my father”→“my sister”のような部分的置換も考えられるし、複数の要素を同時に置換することもできる。いずれも必要性を感じたときに実施すればよいであろう。
