答题完毕，请屏蔽
<P>第一题:选A,理由是A块没有遮挡物体,光线直射A面,而B块有遮挡物所以A亮B暗.</P>
<P>第二题:选A正常,理由是:皮肤颜色柔合.也不灰暗</P>
<P>第三题：如下</P><img src="attachments/dvbbs/2006-4/20064321182191582.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-4/20064321182191582.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><BR><img src="attachments/dvbbs/2006-4/20064321183553784.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-4/20064321183553784.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><BR>
