1) what are the artificial sources of light? 2) what are the manmade sources of light? 3) What is meant by luminous objects? 4) what is meant by non-luminous objects? 5) what are the two types of non-luminous objects? 6) What is linear propagation of light?

排行榜

視覺風格

選項

切換範本

恢復自動保存: ?