Resting is relaxing, and giving your body a break from work. Forms of resting are sitting down, sleeping, and napping. Motion is movement. These two aren't exactly opposites, but I can see where you are going with it.
Motion and rest are relative concepts in physics, meaning that an object can be in motion or at rest depending on the frame of reference. For example, a person seated in a moving train is at rest relative to the train but in motion relative to an observer outside the train. This demonstrates how motion and rest are interconnected depending on the chosen point of view.
Distinguish is similar in meaning to differentiate. An example would be, teachers use tests to distinguish between successful students and unsuccessful students.
how can you distinguish between them
In uniform motion, the velocity of the object is constant: both in magnitude and in direction. In non-uniform one or other (or both) of these will vary.
If the pen is not moving, it is at rest. If the pen is in motion, then it is not at rest.
Rest refers to an object staying still or not changing position relative to its surroundings, while motion refers to an object changing position relative to its surroundings over time. Rest is a state of no movement, while motion involves movement or change in position.
At rest and in motion are relative terms. When we say 'in motion' or 'at rest' we mean relative to something else. If you were travelling in a car for instance, you would be at rest relative to the car but in motion relative to the outside world.
distinguish between book keeping and accounting
It is unclear from your question whether the pen is at rest or in motion as no context or details are provided. If the pen is not moving, then it is at rest. If the pen is moving, then it is in motion.
The electric force between objects that are not in motion is called the electrostatic force. This force is responsible for the attraction or repulsion between charged objects that are at rest relative to each other.
Newton's first law of motion was the law of inertia. When an object is in motion, it stays in motion. When an object is in rest, it stays in rest.
Inertia is the tendency of an object to resist changes in its state of motion. An object at rest will stay at rest, and an object in motion will stay in motion, unless acted upon by an external force. This principle is described by Newton's First Law of Motion.