题目内容：

根据短文内容，从后面的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

Smoggy weather has become common in China. But these days, air pollution levels in the northeastern city of Harbin surpassed the previous record levels.

The city was essentially shut down after PM2.5, fine particulate（微粒的） pollution that is considered dangerous, reached levels of 1,000 micrograms per cubic meter-1.. And therefore schools, motorways and an airport were closed on Tuesday as visibility in some areas of the city dropped to less than 10 meters.

2.. It stated that there is “ sufficient evidence” that exposure to outdoor air pollution causes lung cancer. 3.. Moreover, it’s said that exposure has increased significantly particularly in “rapidly industrial countries with large populations”.

On the Chinese social media site Weibo, many users complained about the pollution and shared their concerns. 4.. Nowadays, there is a sarcastic（讽刺的） play on the expression “serve the people”, as the two have a similar pronunciation.

“5.. There won’t be a sudden outbreak of symptoms, but normally three to five days after the smoggy weather occurs, there is a peak in the number of people seeing doctors,” a doctor said.

A. The impact of air pollution on people will be gradual.

B. Smog has been regarded as the biggest killer nowadays in China.

C. Just days previously, the WHO classified air pollution as a carcinogen（致癌物）.

D. The faster smog comes, the faster it goes away.

E. References to “feed people with smog” have become popular on Weibo.

F. 40 times the safety level reminded by the World Health Organization.

G. And meanwhile, the risk of bladder（膀胱）cancer is also closely connected with it.