Work is a scalar physical quantity hence there is no concept of negative work. When force is applied but there is no displacement, then work done is zero. While when there is certain displacement with respect to force, then work done is positive or we can say somewhat work is done by the body.
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Pushing a box to a direction A to B.
here boy applied force in the direction of box so the work is positive,while the frictional force is in opposite direction so in this case negative work done.
 An object is on a table  here, the gravitational  force is acting but no displacement and also it is perpendicular so the work is 0.

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