I shan't bother to go to the meeting at the school tonight - unless you want to go, of course. Note that in written English, as regards punctuation, the afterthought is usually preceded by a dash.

unless the poem has been expressly written in dialect. This disregard for the grammar of poetry and fiction is connected with another curious feature of English-language values: unlike speakers of ...

Churchill’s scribbled response: “This is the sort of English up with which I will not put.” It’s a great story, but it’s a myth. And so is that so-called grammar rule about ending ...