Bananas, once rarities in Soviet states, are now widely available. 在苏联曾一度是稀有之物的香蕉，现在随处都可见到。
He is that rarity: a true man of science. 他是少有的忠诚于科学的人。
Visits by presidential candidates are a rarity here. 总统候选人很少来这里视察。
The importance of the find lies in its rarity. 该发现的重要性就在于它的稀有。