Complex sentence: It is a narrow sweep of land between 20 and 400 metres wide, encircling a large lagoon 18 km long and 14 km wide, with a surface of 275 km², by far the largest lagoon in Tuvalu.
Split into simpler sentences: It is a narrow sweep of land between 20 and 400 metres wide, encircling a large lagoon 18 km long and 14 km wide. With a surface of 275 km², it is by far the largest lagoon in Tuvalu.