関連ワード:  give three example of artificial light    give an example of artificial light    give three examples of artificial sources of light    give an example of an artificial light source    give an example of natural and artificial light    give three examples of man made sources of light    give an example of man made source of light    give 5 example of artificial light    give five example of artificial light    give one example of artificial light  
結果 : give three example of artificial light