extend
英音：[iks'tend] 美音：[ɪk'stɛnd]
及物动词 vt.
1.延长,延伸;扩大,扩展
Can't you extend your visit for a few days?
你们访问的时间不能延长几天吗?
2.伸,伸出
He extended his hand in greeting.
他伸出手来表示欢迎.
3.致;给予,提供[(+to)]
I would like to extend a warm welcome to our visitors.
我想对我们的来访者表示热烈的欢迎.
4.使竭尽全力[H]
不及物动词 vi.
1.伸展;扩大;延续
The tourist season extends from May till October.
旅游季节从五月延续到十月.
postpone
英音：[pəust'pəun] 美音：[post'pon]
及物动词 vt.
1.使延期,延迟,延缓[(+to/until)][+v-ing]
They postponed sending an answer to a request.
他们耽搁了对一项请求的答覆.
The concert has been postponed to Saturday.
音乐会延迟到星期六.
The sports meet was postponed because of rain.
运动会因雨延期.
2.把...放在次要地位
postpone private gain to the public welfare
把个人利益置于公众福利之后
3.【语】把...放在后面(或句尾)
不及物动词 vi.
1.延迟,延缓
2.(疟疾等)延缓发作(或复发)
两个词意思完全不一样,没有什么可区别的.