The COVID-19(新型冠状病毒) has been spreading world-wide , it is important for us to know how to control it . Please pay attention to the following points : 1 . Don't touch your face . Above all , keep your hands away from your eyes , mouth and nose , all of which serve pathways( 途径 ) for the viruses( 病毒 ) to enter your body . 2 . Wash your hands . If you have to touch your face , wash your hands , getting under the fingernails for 20 to 30 seconds with hot soap and water before . Soaps with surfactants( 表面活性剂 ) can deal with flu viruses . 3 . Cover your nose and mouth . When someone sneezes or coughs , liquid( 液体 ) drops with flu viruses as far as three feet through the air and land on your nose and mouth , so it's best to keep at least an arm's length distance when talking to someone who shows signs of infection( 感染 ) . In order to protect others , cover your mouth and nose with a tissue( 纸巾 ) when you cough or sneeze , and clean your hands afterward . Viruses can live for hours , or even longer when on the skin or other surfaces such as keyboards . 4 . Consider buying a mask(口罩) in case you need it in the future . Some research suggests that masks reduce the risk of getting the flu viruses by as much as 80% . But it also suggests that if you don't wash hands , the mask doesn't work well . So wash your hands and use the mask , especially wearing face masks in crowded places is also useful . 根据短文内容,选择最佳答案。