人生沒有用不到的經歷

過去完成式常出現於住院醫師的病歷中，問及為何要用過去完成式？常常自己也不清楚。

過去完成式常可以過去式取代，但有時則否。
She found a firm and fixed mass in the right breast and had double vision in March this year. A series of examinations indicated that the mass was breast cancer that had metastasized to the brain. 使用過去完成式 (had metastasized) 較過去式佳，因為過去完成式可強調 brain metastasis 在乳癌發現時就 "完成了"。

The patient is a case of hepatitis C. When he first visited our OPD, he had been treated with alpha-interferon for three weeks in XX hospital. 使用過去完成式 had been treated 表達較早在 XX Hospital 所做的治療。

The patient is a case of hepatitis C. When he first visited our OPD, he was treated with alpha-interferon for three weeks in XX hospital. 這句話不通，在本院 OPD 時，怎會在他院以干擾素治療三週？

由上面的例子可知，過去完成式有其使用之時機，使用不當常造成誤解與矛盾。

過去完成式主要在 "特別強調" 事情發生在 "過去的某一段時間"，然而，過去完成式常常可以過去式取代。以下面的對話為例：
Q: Have you ever been to New York?
A: Yes, I had been there for three years. (= I was there for three years.)
Q: When?
A: From April 1996 to May 1999.

既然過去完成式所描述之事情 “已在過去完成”，若病患症狀並未解除，在病程描述中就不宜使用過去完成式。
Chief complaint: Intermittent epigastric pain for one week

(1). He suffered from intermittent epigastric pain for one week, and then jaundice developed with the pain. 此句 jaundice 發生時 epigastric pain 仍然存在。

(2). He had suffered from intermittent epigastric pain for one week, and then jaundice developed with the pain. 此句 jaundice 發生時 epigastric pain 已不存在 (已完成)，與 "with the pain" 會產生矛盾。

(3). He had suffered from intermittent epigastric pain for one week, and then jaundice developed. (jaundice 發生時 epigastric pain 已不復存在，這句是正確的!)