题目

The US government has started a website, Admongo, to help children think critically about the advertising aimed at them. It claims to provide visitors with an “education” through games and other entertainment.        A cartoon man dressed in old time pilot clothing greets visitors to Admongo. Call me Haiz, he says upon arrival in a rocket ship that opens up with a crazy world inside it. Spacey dance music plays in the background as Haiz tells visitors that they need to learn about advertising.        Its inventors say eight to twelve years old is the age kids develop th把四张形状大小完全相同的小长方形卡片（如图1）不重复地放在一个底面为长方形（长为m cm，宽为n cm）的盒子底部（如图2），盒子底面未被卡片覆盖的部分用阴影表示．则图2中两块阴影部分周长和是4n4ncm．（用m或n的式子表示）．