![](https://cos-cdn.shuashuati.com/pipixue-wap/2020-1230-1107-53/ti_inject-812ce.png)
What can we know about the present epidemic ---swine flu? A) The genes of the flu virus come from pigs. B) It will soon spread and cause a pandemic. C) There has been further change in the genes of the viruses. D) It is similar to the influenza pandemic of 1918 to 1919.