5. sound, voice, noise
sound自然界各种各样的声音;
voice人的嗓音;
noise噪音 eg:I hate the loud noise outside.
6. photo, picture, drawing
photo用照相机拍摄的照片;
picture可指相片，图片，电影片;
drawing画的画 eg:Let's go and see a good picture.
7. vocabulary, word
vocabulary词汇，一个人拥有的单词量;
word具体的单词 eg:He has a large vocabulary.
8. population, people
population人口，人数;
people具体的人 eg:China has a large population.