题目：
Scientists are thrilled about some tiny, furry finds. They have discovered two
new species of lemurs on Madagascar, an island _______ off the southeast coas
t of Africa.
① locating
② to locate
③ located
④ been located
答案：③
疑问：为何选③？这是属于何种用法？

(which is/was) located off of 座落于XX之外

了解了，谢谢！