A vast dust storm that blew in from the deserts of Australia’s red centre has blanketed the country’s largest city and eastern coast in a red fog，causing widespread traffic chaos and severe flight delays.
Residents from Sydney in New South Wales to Canberra inland and towns in southern Queensland awoke to a red sky and greatly reduced visibility after the country’s worst dust storm in 70 years blew in overnight. The Sydney Harbor Bridge and Opera House were covered in the red fog and hundreds of people were reported to have breathing problems. Children，the elderly and those suffering from asthma (哮喘) or heart or lung diseases were advised to stay indoors ,as even healthy adults reported "itchy throats" and a metallic aftertaste in their mouths after walking through the thick fog.
Commuters used face masks，originally intended to protect them from the spread of swine flu, to hurry across the blocked streets on their way to work. Some schools were closed and sports activities were called off as the conditions pushed air pollution levels to 1500 times their normal levels – the highest on record.
Passengers at the busy Sydney Airport faced delays of up to six hours for international flights and three hours for domestic trips，and even some international flights were cancelled as visibility was reduced to just a few feet.
Locals，phoning radio stations to express their shock at the red dawn.” It’s like a nuclear winter morning，" tourist Peter Wilson told Daily Telegraph, "It is so terrible." adding that when he awoke the sky was "bright red" and "all the cars were covered in dirt".
The dust hanging over Sydney had largely cleared by midafternoon, although national carrier Qantas said severe delays would last all day because of direction-changed and late-running flights.
The sand storm，which measured more than 310 miles wide and 620 miles long， was caused by dust clouds blowing east from Australia’s dry places，which has been attacked by the worst drought on record. It covered dozens of towns and cities in two states as strong winds swept away tons of topsoil threw it high into the sky and carried it hundreds of miles.
小题1:What was the face mask originally intended for? (No more than 10 words) (2 marks)[
小题2:When did most residents of Sydney discover the vast storm ? (No more than 3 words) (3 marks)
小题3:What do you think the underlined wordQantas is? (No more than 3 words)(2 marks)
小题4:What is the main idea of the last paragraph ? (No more than 10 words) (3 marks)