He works as a cook.和He works at a cook.的表达意思都对吗?

问题描述:

He works as a cook.和He works at a cook.的表达意思都对吗?

第一句正确:他是个厨师.
后面一句也不是完全错误,如果理解成He works at a cook's,就代表他为一个厨师工作了.