Complex sentence: The main island of the group is known as Mainland, and of the next largest, Yell, Unst, and Fetlar lie to the north and Bressay and Whalsay lie to the east.
Split into simpler sentences: The main island of the group is known as Mainland. The next largest are Yell, Unst, and Fetlar, which lie to the north, and Bressay and Whalsay, which lie to the east.