常见例句Her letter were writeen in a happy strain. 她的信是用快乐的笔调写的。The union of A and B, writeen as AUB, is the set of elements which belong to A or B or to both. A与B的并集记为AUB，是属于A或属于B，或同时属于两者的元素的集合。 返回 writeenable