CSS斜分节很少与背景图像

I created 3 div's with each 33% width, that I want to oblique a few degrees. The first and last div should not get a oblique, so that it will only work for the inner content. This also because I want to add 4 divs (25% width) in the near future.I created 3 div's with each 33% width, that I w