The United States faced a deep national crisis in eighteen fifty.

VOA: special.2009.03.19

That was the gravest crisis we faced outside the national security area.

这场危机是我们在国家安全领域外,面对的最严重的危机。

普林斯顿公开课 - 国际座谈会课程节选

Witnesses said they heard an explosion. Sergei Shoigu,Russia's emergency situations minister, described the situation during a live broadcast from the national crisis response center in Moscow.

VOA: standard.2009.11.27

But this was not always the case. Visitors to the Smithsonian's National Museum of American History can see two exhibits dealing with the early years of the AIDS crisis.

VOA: special.2011.06.15

The president talked about what he calls the selfishness and irresponsibility on Wall Street and in Washington that resulted in a national economic crisis.

VOA: standard.2009.05.14