Subject + 曾 + Verb Phrase
The adverb 曾 (céng) means 'once' or 'formerly' and indicates that something happened in the past. It is more formal than 曾经 (céngjīng), which carries the same meaning. For example, 他曾作为队的教练 means 'He once served as the team's coach.'
他曾在这家公司工作过五年。
Tā céng zài zhè jiā gōngsī gōngzuò guò wǔ nián.
He once worked at this company for five years.
我曾去过日本两次。
Wǒ céng qù guò Rìběn liǎng cì.
I have been to Japan twice.
她曾是学校里最优秀的学生。
Tā céng shì xuéxiào lǐ zuì yōuxiù de xuéshēng.
She was once the best student in the school.