"You mustn't start fixing up the closets and taking Aunt Lucy to the doctor because you're the only one at home, " she says.

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"You mustn't do that kind of thing, " his instructor said.

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Not playing can get you down, there are going to be good and bad moments, but you mustn't sulk - you've got to make sure you're ready if needed.

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In London almost everything is labeled 'You mustn't touch, ' and though the label is invisible, it's just as bad, because you know it's there, or if you don't you jolly soon get told.

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What you mustn't then become is just locked in looking back, what I think we've now got to do and what all of us have got to offer the country is a way forward.

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And you mustn't feel entitled to anything.

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"You mustn't play an accent, " Berkery says.

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But you mustn't be obvious.

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"If the British government won't put its own house in order, you mustn't be surprised if there are some of us who will try to find someone else who will make them put their house in order, " told BBC Radio 4's World at One programme.

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Then, he advises telling the child you're disappointed, cheating is unacceptable, and it mustn't happen again.

WSJ: By SUE SHELLENBARGER