如图,把矩形ABCD对折,折痕为MN,矩形DMNC与矩形ABCD相似.则矩形DMNC与矩形ABCD的长与宽之比是____
— Are there any flowers _______ the tree.— No. But there are many birds _________ it.
我同的西沙群岛有着连绵数公里的珊瑚礁,形成珊瑚礁的珊瑚虫属于( )。