C#＋AE中如何通过代码绘制一个圆环？？？怎么构造呀？？？急急急

function nTabs(thisObj,Num){
if(thisObjclassName == "active")return;
var tabObj = thisObjparentNodeid;
var tabList = documentgetElementById(tabObj)getElementsByTagName("li");
for(i=0; i <tabListlength; i++)
{

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