He is learning to develop the film negatives.他学洗相片.Color positive emulsions basically perform in the same way that color negatives do.彩色正片的彩色再现过程，基本上和彩色负片相同。Two negatives make an affirmative.两个否定构成肯定.In the past we have ...
那个盲人用手杖敲打人行道的地面.The blind man tapped the sidewalk with his cane.我们称这种新字母表为盲人用点字法.We will call this new alphabet'Braille '.盲人用竹竿点点探探,走得极缓慢.Blind bit of test the waters with a bamboo pole and going very slow....