1. The man is drawing cartoons on a drawing board. He has a pen on his right ear. What do you think he is doing? (Would you check this writing?)
2. The dogs are playing with balls.
3. Each dog is playing with a ball.
4. The dogs are playing with a ball.
(Are the three sentences the same in meaning?)
1. OK
2, 3, and 4 are similar but not identical.
In 2, there are two or more dogs and two more balls.
In 3, there are several dogs, and each one is playing with a ball of its own.
In 4, all the dogs are playing, and there's only one ball.