According to the passage, scientists have discovered that influenza viruses ______. New strains of viruses are transmitted to m

admin2009-05-28  36

问题 According to the passage, scientists have discovered that influenza viruses ______.
New strains of viruses are transmitted to man by ______.

选项 A、A type of wild pig
B、diseased lower animals
C、a group of migrating birds
D、a variety of means

答案D

解析
转载请注明原文地址:https://jikaoti.com/ti/y69MFFFM
0

最新回复(0)