Complex sentence: The Snowy Mountains, known informally as "The Snowies", an IBRA subregion, is the highest mountain range on the island country/continent of Australia and contains the Australian mainland's highest mountain, Mount Kosciuszko, which reaches a height of above the ground.
Split into simpler sentences: The Snowy Mountains, known informally as "The Snowies", is an IBRA subregion and the highest mountain range on the island country/continent of Australia. It contains the Australian mainland's highest mountain, Mount Kosciuszko, which reaches to a height of above the ground.