前天用英语表示为 "the day before yesterday"。这个短语来源于古英语中的 "þærra geares"，其中 "þærra" 意为 "前"，"geares" 意为 "昨天"。
例句：
"I saw him the day before yesterday." (我前天看见了他。)
"I finished the project the day before yesterday." (我前天完成了项目。)
"I talked to her the day before yesterday." (我前天和她说话了。)