如图,平行四边形ABCD的对角线交于点O,且AB=5,△OCD的周长为23,则平行四边形ABCD的两条对角线的和是( )
A:18
B:28
C:36
D:46
读我国某区域图,图中阴影部份地形区是( )
Neither Jam nor his parents _______ places of interest here since they came to China.
如果一次失血不超过400毫升,所丧失的血浆成分和血细胞可以在短期内得到补充而恢复正常.