![](https://cos-cdn.shuashuati.com/pipixue-web/2020-1231-2005-12/ti_inject-812ce.png)
It can be inferred from the first paragraph that
A.
the 1957 influenza infected 250,000 people in America
B.
Asia was the cradle of the 1957 influenza pandemic in America.
C.
Maurice Hilleman went to Asia to Collect the sample of the influenza
D.
it was quite time-consuming to study the genetic structure of the influenza