I'm emailing to introduce my friend Tom, who is applying for your marketing position.

我寫這封信是想介紹我的朋友湯姆，他正在應徵貴公司的行銷職缺。

A close friend from accounting helped me prepare the quarterly budget report last night.

會計部的一位好朋友昨晚幫我準備了季度預算報告。

While traveling to Tokyo for the trade show, I stayed with an old friend downtown.

去東京參加商展時，我住在市中心一位老朋友家。