rubbish is hidden behind walls. Garbage cans are often of little use, making cleaners must rush all day long and also by night to clean the problems are becoming more and more serious a
China, my motherland, is really a great now her sixtith birthday is stands in Asia and lies on the west coast of the ocean. China covers 9,600,000square kilometers. People of abo
Phonograph - History The first great invention developed by Edison in Menlo Park was the tin foil phonograph. While working to improve the efficiency of a telegraph transmitter, he noted that the tape of the
科学杂志 Founded in 1880 on $10,000 of seed money from the American inventor Thomas Edison, Science has grown to become the world's leading outlet for scientific new