代码分别是：
代码一：
<a href="http://www.ubuntu.com/"><img src="http://www.ubuntu.com/countdown/banner1.png" border="0" width="180" height="150" alt="The next version of Ubuntu is coming soon"></a>
代码二：
<a href="http://www.ubuntu.com/"><img src="http://www.ubuntu.com/countdown/banner2.png" border="0" width="180" height="150" alt="The next version of Ubuntu is coming soon"></a>
代码三：
<a href="http://www.ubuntu.com/"><img src="http://www.ubuntu.com/countdown/banner3.png" border="0" width="180" height="150" alt="The next version of Ubuntu is coming soon"></a>
