求翻译：由于物体的体面是多方面的，体面朝光源的方向不同，接受光线的强弱程度就有差异，从而产生了千变万化的明暗层次。在写生作业中，要正确地运用明暗方法充分地表现物象的立体感，就要理解光源方向和体面角度变化所形成的明暗规律，这将有助于我们自觉地描绘明暗，表现物体的立体形象和空间效果。是什么意思？

As the objects are many decent, decent toward the light source in a different direction, there is acceptance of differences in the intensity of light, resulting in ever-changing shades. In the painting operation, the correct use of light and shade to full performance of the method of three-dimension

The object of decent is multifaceted, decent toward the source of the light rays in different directions, the acceptance of strong or weak, there is a gap between the 1000 change of 10,000 levels of brightness. sketches in operation, it is necessary to correctly use shade fully epiphany methods, we

Because the object dignity is various, the dignity faces the photosource the direction to be different, accepts the light the strong and the weak degree to have the difference, thus has had the e

Since the object of decency is multifaceted, decent looking toward the light source in different, accept the light intensity level, there are differences, resulting in ever-changing light levels. Sketching in the job, to properly using the method of light and fully visible phenomena of the stereosco