Commuters wearing face masks were seen on the streets and subways of major cities yesterday despite the early summer heat, saying they have grown more cautious of the A(H1N1) flu after seeing confirmed cases so close to home.

"The government is reacting quickly, but I'm still worried about the spread of the virus inside trains and planes," said a middle-aged woman Li, who wore a large face mask and dark sunglasses as she left a subway station in Beijing.

The mainland quarantined several hundred people yesterday who had been in contact with two Chinese men confirmed to have contracted the virus.

Sun Naiqing, a veteran Beijing cabbie, doesn't dare take passengers from the airport.

"I'd rather stay downtown, and I don't take passengers with masks and I don't turn on the air-con," he said at his wheel. "The scene of travelers wearing masks is scary."

Jia Peng, spokesman for the Beijing subway, downplayed worries for passengers yesterday and promised the metro will disinfect trains and keep the air inside carriages clean.

Lu, a 19-year-old overseas student who had contracted the virus, traveled from Canada to his hometown in Shandong province and stayed at a crowded hotel before setting foot on several tourist sites, including the Great Wall and the bar district near Houhai in the capital.

Questions:

1. How many people were quarantined yesterday?

2. Which country was the 19-year-old Chinese student who brought back the virus to China studying in?

Answers:

1. Several hundred.

2. Canada