According to the passage, scientists have discovered that influenza viruses ______ .
A: cause ill health in wild birds
B: do not always cause symptoms in birds
C: are rarely present in wild birds
D: change when transferred from animals to man
A: cause ill health in wild birds
B: do not always cause symptoms in birds
C: are rarely present in wild birds
D: change when transferred from animals to man
举一反三
- According to the passage, scientists have discovered that influenza viruses_____.
- Who should be monitoring the wild birds and preparing to tackle disease outbreaks A: Health officials in Asia. B: Health officials in Europe. C: Health officials in America.
- Owing<br/>to the environment pollution, 30 percent of wild life, birds, and<br/>fish are currently ______ with extinction.
- According to the passage, to do the "effect to effect" reasoning is to reason _____. A: from cause to effect B: from effect to cause C: from effect to effect and on to cause D: from effect to cause and on to another effect
- This passage supports the belief that ______. A: exact reasons for migration are not known B: glaciers caused birds to migrate C: the ancestral home of birds was the tropics D: birds migrate because of changes in temperature