study的過去式和過去分詞？

　　study 雙語例句

　　例句 1. Reading for pleasure and reading for study are not the same.

　　讀書以自娛和讀書以學習是不相同的。

　　例句 2. We will study the report carefully before making a decision.

　　我們將認真研究這份報告，然后再作決定。

　　例句 3. They studied the geographical distribution of the disease.

　　他們研究了這種疾病的地域分布情況。