【简答题】The formation of "flu" from influenza is a front and back _____________.
【简答题】The influenza, or flu virus, is a ____ nightmare.
【简答题】Influenza is a viral infection. The flu 26____which caused the 1918 27____was 25 times more deadly than normal and it caused more deaths than the First World War. The consequences of a massive 28____c...
【单选题】According to CDC, birds carry every known subtype of influenza A and can transmit the flu directly to humans.
【单选题】Flu is a contagious respiratory illness caused by influenza viruses that infect .