formal error的用法和樣例：
例句
- Data-format validation often triggers error pages or requires the client to re-enter incorrectly formatted data.
數據格式驗證經常觸發錯誤頁面或要求客戶機重新輸入格式錯誤的數據。 - Often, when writing a parser that is able to detect errors in the format of the input stream, we want it to communicate to the user where the error happened within that input.
通常，在編寫一個可以檢測輸入流的格式錯誤的分析器時，我們會希望它可以告知用戶，錯誤發生於輸入的何處。
