Ответ:

flu - any of several virus diseases marked especially by respiratory or intestinal symptoms

You can catch the flu when someone near you coughs or sneezes. Or, if you touch something the virus is on, like Ellen and Jack's phone or doorknob, and then touch your nose or mouth, you could catch the flu. The flu virus can live on a surface like a book or doorknob for a number of hours

Объяснение:

What's is flu?

Flu is one of the most common and widely spread illnesses. Speaking about influenza, we should mention that it’s a viral infection. When someone in your surrounding has the flu you should be careful not to catch it. It is usually manifested by fever, strong headache, muscle pain, cough, running nose, sometimes sore throat or earache.Depending on the level of heaviness it can even turn into pneumonia. In that case hospitalization is necessary. At the moment, there are three basic forms of influenza known in the world: A, B and C. All of them can be treated just by different methods and pills.