There are plenty of teachers who use blogs to teach Englsh, like me. Here you are a link to one of those with a lot of exercises to practise:
http://elenacarriles.wikispaces.com/THE+SAXON+GENITIVE but you also have these links: click
here or this
one (but this includes past tenses)
To finish with, try to do oral exercises using this structure:
- Sara has a dog. It's black --- Sarah's dog is black
- Joe has a cat. It's white --- Joe's cat is white
Howerver, be careful with nouns ending in -S or sibilant sounds like in the following examples. The pronunciation changes a lot:
- Alice has a daughter --- Alice's daughter (you have to pronounce an extra syllable /ælɪsiːz/)
However, you don't write or pronounce the extra 'S with plural forms
- My cousins have a house --- my cousins' house ( /ˈkʌzənsiz/ )
Notice that if it's ending in -S you don't write an extra -s like in
the Simpsons' dog.
See you in class.