A、Ⅰ°深覆<img alt="说明:01" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/86a6626c-7513-4c41-9710-7ba6cc53256d.jpg" width="14" height="14" />
B、Ⅱ°深覆<img alt="说明:01" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/86a6626c-7513-4c41-9710-7ba6cc53256d.jpg" width="14" height="14" />
C、Ⅰ°深覆盖
D、Ⅱ°深覆盖
E、Ⅲ°深覆<img alt="说明:01" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/86a6626c-7513-4c41-9710-7ba6cc53256d.jpg" width="14" height="14" />
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