Can we have 'unless' in a negative sentence?

[moonlike]

Hi
what I have been taught and leaned so far was that 'unless' means 'if not', therefore it comes in a positive sentence. I went through Practical English Grammar as well, but I couldn't find a negative structure with 'unless'. However, in a worksheet I bumped into this sentence and I was shocked. Could you tell me if it's possible and if there are any exceptions or rules?

Take your camera unless you haven't brought it.

Thanks a lot.

[emsr2d2]

Hi
what I have been taught and leaned so far was that 'unless' means 'if not', therefore it comes in a positive sentence. I went through Practical English Grammar as well, but I couldn't find a negative structure with 'unless'. However, in a worksheet I bumped into this sentence and I was shocked. Could you tell me if it's possible and if there are any exceptions or rules?

Take your camera unless you haven't brought it.

Thanks a lot.

My first instinct was to say that that sentence was nonsense. Then I reconsidered. It is possible. Imagine this scenario:

You have gone on holiday to Kenya to watch wild animals - a safari holiday. On the morning of the first trip to see some animals, the tour guide hands you a piece of paper with suggestions of things to take with you for the day. He suggests that you take a hat, some mosquito repellent and a long-sleeved shirt. He also suggests that you wear comfortable shoes. He also suggests that you take your camera.

When he wrote the last sentence, he realised that some people might have forgotten to pack their camera when they left home to fly to Kenya. So he adds "unless you haven't brought it", meaning "unless you have not brought your camera from your home country to Kenya". Obviously, if you haven't brought your camera to Kenya, you can't take your camera with you on safari for the day. Consequently, the phrase "Take your camera unless you haven't brought it" is possible!

[moonlike]

My first instinct was to say that that sentence was nonsense.

Thanks. So grammatically speaking, it's rare to have such a structure. Am I right?

[5jj]

... it's rare to have such a structure. Am I right?

Such structures are certainly not common, but I wouldn't say they are rare. The following do not sound unnatural to me:

I'll tell George tomorrow, unless he doesn't come.
He won't turn up, unless he hasn't heard about the strike.
I usually stay open till midnight unless there is nobody in the bar.

[emsr2d2]

My first instinct was to say that that sentence was nonsense.

Thanks. So grammatically speaking, it's rare to have such a structure. Am I right?

As 5jj said, they're not rare. I think my initial reaction to it was based on the fact that the particular example you had given is probably not commonly used. 5jj's examples are quite normal.

[Barb_D]

As a matter of style, I don't like them much because it makes the reader have to untangle the thought. Do this.. unless I haven't done that. So if I have done that, then I do this. Hmm.

That's why I suspect you won't see it in writing as much.

However, I suspect in speech we use it much more often, usually because we realize that there might be a situation in which something we've just said won't apply in some situations (like ems's camera example) so we amend our original statement.