Foam extinguisher can be used to put out general fires such as wood and cotton cloth; Liquid carbon dioxide fire extinguishers can be used to extinguish fires such as books, archives, expensive equipment and precision instruments. Dry powder fire extinguishers can be used to put out general fires, as well as fires caused by oil and natural gas. According to the scope of application of fire extinguishers, libraries or studios that store precision instruments should use liquid carbon dioxide fire extinguishers, so B.