Tā / píng / shí / shí / fēn / jǐn / shèn / dàn / zhè / cì / hái / shì / qiān / lǜ / yī / shī / lòu / kàn / le / yí / ge / zhòng / yào / shù / zì

他平时十分谨慎，但这次还是千虑一失，漏看了一个重要数字。

He is usually very careful, but this time he still made a mistake and missed an important number.