单项选择题
A.E[att]B.E[att="val"]C.E[att~="val"]D.E[att^="val"]
A.enable=enableB.disabled=disabledC.checked=checkedD.E[att^="val"]
A.E:first-childB.E:nth-child(n)C.E:nth-of-type(n)D.E:last-child