More than 20countries have found cases of the new H1N1 influenza virus （病毒）。In all around 1,500 cases and 30 deaths have been true, But most have been reported in Mexico and, to a much lesser extent, the United States. The virus was discovered in Mexico in the middle of March.

On Tuesday, federal officials in the United States advised school not to close any more when they have cases. Then new health secretary , Kathleen Sebelius, said the virus does not seem to be as severe （严重的） as once thought.

 The Word Health Organization will not declare an influenza pandemic （流行全世界的） unless a virus becomes widespread in at least two areas of the world. The W. H. O. is advising people to wash their hands often with soap and water. And it says there is no danger of infection （传染） from eating well – cooked meat form pigs. The danger of H1N1 may have eased （减轻） in recent days. But public health officials point out that flu viruses can return more aggressively （攻击性地）after a few months. That happened with the so-called Spanish flu of 1918 which killed millions worldwide.

1．Which country has most of the cases of the new H1N1 influenza virus?

     A．The United States           B．Mexico

     C．We don’t know             D．One of the 20countries

2．Why were schools in the United States advised not to close any more when they have cases?

A．The virus seems to be as severe as once thought.

B．The virus seems to be more severe than once thought

C．The virus doesn’t seem to be less severe than once thought

D．The virus seems to be less severe than once thought.

3．When will the World Health Organization declare an influenza pandemic?

A．A virus becomes widespread in least three of the world

B．A virus becomes widespread in at least one area of the world

C．A virus becomes widespread in more than one area of the world

D．A virus becomes widespread in more than two areas of the world.

4．Is there danger of infection from eating well-cooked meat from pigs?

A．No, we can’t eat well-cooked meat from pigs.

B．No, there isn’t. We can eat well-cooked meat from pigs.

C．Yes, there is. We can’t eat well-cooked meat from pigs

D．Yes, there is. We can eat well –cooked meat from pigs.

5．What will happen to flu viruses after a few months according to the passage?

A．They can return more aggressively.

B．They may have eased

C．They had killed millions of people worldwide by 1918.

D．They may disappear and won’t return.