I.
1.The USA is an enormous country, more than two times of European Union.
2.The USA is a land of extremes. It's one of the hottest and coldest place in the world.
3.About half of Australia's population go to one of the fantastic events on Australia day.
4.One of the half of Australia's population celebrate Australia day at home or at the beach with their family and friends.
5.They have barbecues and they watch Australian of the year award on television
II.
1.I found it difficult to understand what my new American friend asked me on the first days but it's OK now.
2.Have you made the acquaintance of any people from English speaking countries?
3.Australians are native speakers because they use English as their mother tongue.
4.What countries speak English as their official language?
5.New Zealand and Australia are both surrounded by the sea.
III.
1.
1.show=>shown
2.the middle of
3.chose=>chosen
4.many=>much
5.as well as
6.bar=>bars
7.provides=>provide
8.have=>had
9.healthy=>health
10.easy=>easily