China, a country with 145 million elderly people, will remain _______ ageing society during this century, according to _______ Chinese population experts. A. /; the
某段铁路所有车站共发行20种普通车票,那么这段铁路共有车站数是 ( ) A.4 B.5 C.8 D.10
代数式a2+4a—1的值为3,则代数式2a2+8a—3的值为________.
下图是某二倍体动物细胞分裂的简图,请分析回答: (1)A图所示细胞时期为 。 (2)B
No trip to Chicago is complete without a visit to the Art Institute, which is the second largest art museum in the nation. Opening hours: Mon - Wed & Fri - Sun, 10:30 am - 5 pm; Th
一个物体在水平面上受到恒定的水平力作用,从静止开始运动,经过时间t后撤去外力,物体继续运动,其v-t图线如图所示,则在此过程中,水平拉力