My extension is two four double 0.

　　我的分機(jī)號(hào)是2400。

　　The extension of the subway will take several months.

　　擴(kuò)建地鐵需用幾個(gè)月時(shí)間。

　　He's been granted an extension of the contract for another year.

　　他的合同獲得延期一年。

　　You can reach me at 637-2335, extension 354.

　　你可以打637-2335這個(gè)電話(huà)號(hào)碼，轉(zhuǎn)分機(jī)354，與我聯(lián)系。

　　What's your extension number?

　　你的分機(jī)號(hào)碼是多少？