您需要这样做:

#menuBar #test2 a:hover{
   background:url("../images/btTest.jpg") no-repeat top;
} 

要这样:

#menuBar #test2:hover a {
  background:url("../images/btTest.jpg") no-repeat top;
}

要使它在移动到 .subMenu 时保持原状.如果您愿意的话，这将不适用于IE6.

To get it to stick when you move to the .subMenu. This will not work for IE6 (if you care).

还有这些:

#menuBar #test2 a:hover + .subMenu { //submenu show up
  display:block;
} 

#menuBar li .subMenu:hover {  //keep submenu show up when hover in submenu
  display: block; 
}

应该可以被这样替换:

#menuBar li:hover .subMenu {
  display: block;
}