The world's largest online community is grappling with challenges it faces in protecting intellectual property rights (IPR), says an expert.

The US Congressional International Anti-Piracy Caucus on Wednesday listed China as one of the world's five-worst offenders in violating copyright. The other four nations are Canada, Mexico, Russia and Spain.

But Wang Chunyan, an expert in intellectual property studies at Renmin University of China, said the nation is taking on the challenges.

"We never denied it. But the government is trying its best in seeking a proper way to balance the interests of various sides and people's rights to obtain information," she said.

She was responding to criticism from the anti-piracy caucus, made up of more than 70 members of the Senate and House of Representatives. The caucus claimed piracy of copyrighted movies, music, video games and other entertainment had reached "alarming levels" in the five countries. They added that it "cost the US copyright industries and the millions of Americans who work in these companies billions of dollars".

The group claimed the Chinese government "has permitted piracy to fully contaminate the online marketplace via an array of nefarious illegal websites, file storage sites (and) user-generated content sites."

"Despite the Chinese government's many public assurances that it is committed to combating copyright piracy, little action has been taken against infringing online activities," claimed the report.

China's largest Internet search engine, Baidu, was said to be "responsible for the vast majority of illegal downloading of music in China, deriving significant advertising revenue."

Last year, China closed 192 websites that profited from copyright infringement and uncovered over 5,700 cases of copyright infringement, Commissioner of the State Intellectual Property Office Tian Lipu said.

The World Trade Organization in March confirmed China's achievements and rejected most items of a US allegation on China's IPR protection.

Questions:

1. What are the five nations listed as the world's worst offenders in violating copyright?

2. Who makes up the US anti-piracy caucus?

3. What is China’s largest Internet search engine?

Answers:

1. China, Canada, Mexico, Russia and Spain.

2. 70 members of the Senate and House of Representatives.

3. Baidu.