如何在IE 7中强制li项目为父容器宽度的100％？

I'm applying a background color to my list items. But in IE7, my child list items are not being rendered the full width of the parent UL item. Instead, it appears that they act like inline elements (their width only extends to the boundary of the text that makes up their content), even though I've set the child li elements to display:block;I'm applying a background color to my list item