为什么这不起作用？？varsheep=function(options){this.options={sizes:100,eat:100,colors:'white',running:function(){returnthis.sizes+this.eat;}}};varblacksheep=newsheep({colors:'black'});alert('blackcsheepcoloris'+blacksheep.colors);//errorundefinedalert('blackcsheepcoloris'+blacksheep.options.colors);//itre