S denoting the two sets to evaluate as true logical ,那么这个对象就属于两个集合的并集(逻辑
2.
This can be worked out to taking the union of the two sets and then removing from it the elements belonging to the intersection of the two sets 这可以取两个集合的并集,然后从中删除属于两个集合的交集的元素得到。