指出不属于热泪的原因:
A.异物入目
B.泪道阻塞
C.天行赤眼
D.聚星障
E.天行赤眼暴翳
参考答案:B
已知集合A={1,2,3,…,2n(n∈N*)}.对于A的一个子集S,若存在不大于n的正整数m,使得对于S中的任意一对元素s1,s2,都有|s1-s2|≠m,则称S具有性质P.
(Ⅰ)当n=10时,试判断集合B={x∈A|x>9}和C={x∈A|x=3k-1,k∈N*}是否具有性质P?并说明理由.
(II)若集合S具有性质P,试判断集合 T={(2n+1)-x|x∈S)}是否一定具有性质P?并说明理由.
Are a firm’s demand for labor and a firm’s demand for physical capital more elastic in the long run or in the short run Demand for labor more elastic in the: Demand for physical capital more elastic in the:()①A. short run short run ②B. long run long run ③C. short run long run
A. ①
B. ②
C. ③