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Researchers have, until recent times, concentrated on the reasons for smoking and therefore overlooked the differences between smokers and nonsmokers. |
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In recent times researchers have given much attention to the differences between smokers and nonsmokers in the hope of finding a single reason for smoking. |
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On the assumption that there can be only one reason for smoking, researchers have from the start concentrated on the differences between smokers and nonsmokers |
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It has only recently been appreciated by researchers that the differences between smokers and nonsmokers spring from their attitude to smoking. |
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Until recently researchers assumed there must be a single reason for smoking and therefore looked first for differences between those who smoked and those who did not. |