For the past few days, Shanghai resident Grace Zhang and her husband have been preparing for a special dinner party this Saturday.

Zhang has made sure her apartment in Jing'an district is well stocked with two dozen candles among other things.

But guests will not be surprised when the lights go out.

"A few friends will come to this 'lights-out' party of ours," said Zhang, 27, an office worker at a trading company.

"We will switch off the lights at 8:30 pm after dinner, then light the candles and play games," Zhang said.

Guests at her candlelit bash are just some of the people across the globe who will mark the third "Earth Hour" at 8:30 pm in their time zones by turning off lights and electrical appliances for one hour on March 28.

The event was launched by WWF Australia in 2007 as part of a worldwide effort to raise awareness of climate change. Last year, many more cities around the world joined in.

"This year's event will be the biggest one yet," Li Yuan, of the WWF's Shanghai office, said yesterday.

"So far, Hong Kong, Shanghai and Baoding city in Hebei province have officially announced their involvement in Earth Hour.

"More cities in China are taking part. Countless individuals, businesses, organizations and communities have promised to turn off their lights," Li said.

By Tuesday, 80 countries and regions, 1,760 cities, towns or municipalities, 5,259 organizations, 7,382 schools, 18,160 businesses and countless individuals had also signed on to the Earth Hour website at www.earthhour.org to pledge their support, organizers said.

Apart from Shanghai's iconic Oriental Pearl TV Tower and World Financial Center, Beijing's Bird's Nest national stadium will also take part in the event by switching off their lights for an hour.

A live radio program on "Earth Hour" will be broadcast from Shanghai's TV tower involving participating cities in three different time zones, organizers said.

Questions:

1. At what time will people in their local time zones turn off their lights and appliances this Saturday?

2. Who launched Earth Hour?

3. What Beijing landmark will turn off its lights?

Answers:

1. 8:30 pm.

2. WWF Australia.

3. Bird’s Nest national stadium.