After nearly eight years of preparation and six rounds of trial operation, Shanghai is ready for the 184-day World Exposition which opens May 1.

Some 189 countries and 57 international organizations have confirmed their participation in the largest-ever expo which is expected to attract more than 70 million visitors from all over the world.

During the expo trial, more than one million people savored the charms of the marvelous pavilions at the World Expo site.

Yang Xiong, executive vice mayor of Shanghai, said Wednesday, through the expo trial, the organizers gained experience, found problems and made adjustments.

"We examined facilities, improved systems, trained staff and improved services thanks to the trial rounds," he said.

Volunteers: at your service

Li Lun, a volunteer on the Expo Axis, will serve for the first two weeks of the expo. His voice has gone hoarse after three days of testing operation.

"During the peak hours in the morning and at noon, we were asked questions almost every 10 seconds," said Li, a postgraduate student at Shanghai-based Fudan University. "Some of my schoolmates have lost their voice."

The 24-year-old has done voluntary work before, but it's the first time for such a big event.

"Every day after work, our team leader asked us what the most frequently-asked questions were and what the best answers are," he said.

Li is making use of the last few days before the expo officially opens to learn about the event as much as possible to be better prepared.

Shanghai has more than 72,000 volunteers at the 5.28-square-kilometer World Expo site, while another 100,000 volunteers work at the service stations in the city's 18 districts and counties.

Xia Kejia, director of the Expo site volunteer department, said more than 9,000 Expo site volunteers were trained during the trial operations.

Due to inadequate on-site practice and communication issues between organizers and volunteers, problems surfaced.

Visitors complained there were not enough volunteers, and that some volunteers were not familiar with the site and failed to answer visitors' questions, Xia said.

Xia said measures have been taken to improve the situation, including increasing the number of volunteers by 20 percent and sending volunteers the latest information by text message.

"We're trying our best to avoid saying 'I don't know' to visitors," Xia said.

Tang Xiaoting, a teacher at Shanghai Maritime University, did reception work for the International Exhibitions Bureau in 2002 as a high school student and also served at the 2008 Beijing Olympics.

As a "veteran" volunteer, Tang said though the volunteer's work is usually simple and trivial, young people need to improve their patience and time management and communication capabilities.

"So, we also have to get prepared psychologically and serve the expo with a proper attitude," said the 27-year-old.

Li Lun agreed. "We should be prepared for hard work and complaints," he said.