[判断题]创伤急救时，外部出血立即采取止血措施，防止失血过多而休克。
A.正确
B.错误

Although we already know a great deal about influenza, and although the World Health Organization is constantly collecting detailed information from its chain of influenza reference laboratories throughout the world, it is extremely difficult for epidemiologists (流行病专家), who study infectious disease, to predict when and where the next flu epidemic will occur, and how severe it will be.
There are three kinds of influenza virus, known as A, B and C. Influenza C virus is relatively stable and causes mild infections that do not spread far through the population. The A and B types are unstable, and are responsible for the epidemics that cause frequent concern. Following any virus attack, the human body builds up antibodies which confer immunity to that strain of virus, but a virus with the capacity to change its character is able to by-pass this protection. Variability is less developed in the influenza B virus, which affects only human beings. An influenza B virus may cause a
A. Man has obtained a great deal of knowledge about influenza
B. The occurrence of influenza is still unpredictable
C. Influenza is being studied extensively and systematically in many countries in the world under the guidance of World Health Organization
D. No reliable treatment of influenza has yet been found.