Correct or improve the translation of the following English sentences.原文：Scientists are confident about the formation of coal. 译文：科学家对煤是怎样形成的很自信。改译：

Correct or improve the translation of the following English sentences.原文：Scientists are confident about the formation of coal. 译文：科学家对煤是怎样形成的很自信。改译：

科学家知道煤是怎样形成的。