曾老师的分析有道理。workfrom home 可视为固定表达，指通过网络系统“在家工作；在家上班；在家办公”。但补充一点，work at home 其实也可表示这样的意思。比如《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 (=do your work at home instead of at a company office)。补充例句如下：

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

I needed a job which would enable me towork at home. 我需要一份能够在家里干的工作。

Ideally, I'd like to work at home but it'sjust not practical. 对我来说最理想的是在家上班，可这根本不现实。

If it’s all the same to you, I’d ratherwork at home. 如果对你来说没什么差别，我宁愿在家中工作。

I want to work at home on a Tuesday but asit turns out sometimes it’s a Wednesday or a Thursday. 我想周二在家工作，但实际上有时却是周三或是周四。