- the dog's ball (the ball belongs to the dog)
- the flower's petals (the petals belong to the flower)
- the car's wheels (the wheels belong to the car)
Discuss with your child how you can say that these parts belong to the cat. Point to different parts and ask them to tell you 'the cat's tail', 'the cat's whiskers', etc. When they can talk the picture, ask them to write the words. If they write 'the cats tail', ask how many cats they can see. How can we make sure the reader knows there is only one cat? We use an apostrophe before the s. If you print out the picture, or use one from a magazine, they could label the picture.
The process is usually the same for a proper noun that already ends in s. Examples are Charles's car, James's book. When possession is shown in this way, the additional s is pronounced. For information on trickier apostrophes, click here.