Когда в языке пишется окончание 's, а когда s'

В единственном числе при образовании притяжательного падежа 's
Pupil's book
Учебник ученика
О множественном числе при образовании притяжательного падежа s'
Pupils' books
Учебники учеников

Исключения -men's,children's,women's

Когда существительное в единственном числе,то пишется 's,а когда во множественном,то s'.

1) One country is situated on the island.

2) There are three Australian deserts on the island. The Great Sandy Desert is situated in the North West of Western Australia straddling the Pilbara and southern Kimberley regions. The Great Victoria Desert is located in Western Australia and South Australia. The Gibson Desert covers a large dry area in the state of Western Australia.

3) The biggest lake on the continent is Lake Eyre.

4) The Murray River is one of the most important rivers in Australia.

5) the Blue Mountains are situated in New South Wales.

6) Canberra is the capital of Australia.

8) I can see Ballarat,Shepparton,Albany,Gladstone and so on.

New Year is one of my favourite holidays of the year.

Starting from the end of November all the shops, offices and other places in the street wear special, festive decorations and remind a fairy tale. As for my family, we start decorating our flat in the middle of December.

My father usually buys a tall Christmas tree and sets it up in the living-room. For the New Year feast my mum cooks special dishes. And we all prepare postcards and gifts for people we love and value.

New Year’s Eve always seems to me magical and unforgettable. At midnight my dad fills everyone’s glasses with champagne and says the toast to welcome the coming year. We wish each other a happy New Year and make a wish and then exchange gifts.

I really enjoy New Year and every year I look forward to celebrate it with my family.