work at home还是work from home

有如此一个句子：

Rather than going into an office, a lot of people are connected to the Internet and now work from home. 目前有很多人都不去办公室，而是连接到网络，在家工作。

请问这里为何用 work from home，而不需要 work at home 呢？

曾老师的剖析有道理。workfrom home 可视为固定表达，指通过互联网系统ldquo;在家工作；在家上班；在家办公rdquo;。但补充一点，work at home 其实也可表示如此的意思。譬如《朗文当代英语词典》在 home 词条用黑体字列出了两条短语 work from / at home 。补充例句如下：

More people elected to work at home. 更多的人选择在家里工作。

I needed a job which would enable me towork at home. 我需要一份可以在家干的工作。

Ideally, Id like to work at home but itsjust not practical. 对我来讲最佳的是在家上班，可这根本不现实。

If itrsquo;s all the same to you, Irsquo;d ratherwork at home. 假如对你来讲没什么差别，我宁可在家里工作。

I want to work at home on a Tuesday but asit turns out sometimes itrsquo;s a Wednesday or a Thursday. 我想周二在家工作，但事实上有时却是周三或是周四。