The streets of Dalian, Liaoning were covered by snow a week before Spring Festival. However, instead of staying at home, Li Chunyuan, a junior one student at No. 42 Middle School, went out with her classmates. They made posters themselves and     1     people not to set off fireworks.

The students did this to try to     2     air pollution. Since January, many cities in China have seen a lot of foggy days. In Beijing, only five days in January were free of smog. Smog is dirty air that looks like fog and smoke.

An official for the Ministry of Environmental Protection told Beijing news that PM2.5 pollution is the     3     problem with air pollution. PM2.5 to pollution with small particles 2.5 micrometers or less in diameter(直径).

According to the Chinese Academy of Science, two major factors that cause PM2.5 are motor vehicles and the burning of coal.

Poor air has done harm to people’s health. Children and the elderly are more at risk. Areport form Beijing Children’s Hospital shows that from Jan 5th to 11th,     4     the patients in the internal medicine department came for respiratory(呼吸道的) problems.

To respond to the air problem, the Chinese government and many Chinese people have started to     5    . People are called on to make full use of energy and resources and cut down on energy use.

Beijing announced plans to use clean fuel in government vehicles and plant trees. It also asked citizens to     6     fewer fireworks for the Spring Festival celebration.

Three students from No. 4 High School in Beijing wrote a report to advise how to fight the air pollution. They suggested that cars with large emissions(排放) should be banned(禁止) and factories should be     7     watched.

“We hope more people will join us in making a difference. With all our     8    . The blue skies will certainly return for good,” said Shi Yucong, one of the three students.

Indeed, air problems and environmental protection have become a concern for the whole nation.

If you find a bird nest, you will have a good place to watch and know about birds. Birds sit on eggs and take care of their     1     from April to June. Because baby birds are too     2    , parent birds often go and look for     3     and come back in several minutes. So it is the best time to watch the birds. Remember not to get too close. You’d     4     use binoculars.

However, climbing up a tree to watch birds may be     5    . Why don’t you     6     a nest? A good bird nest must be very fine, strong, thick and     7    . If you want to make one, please follow these steps.

Each nest must have six boards. Don’t make the boards too slippery.

Dig a small     8     in the front of the nest as a “door”. The door is big enough for birds to fly in or out     9    .

Make sure the rainwater can’t go into the nest.

One piece of the boards should be easy to open.

Don’t forget to colour the nest. Make it look like a     10     one.

After you get this nest ready, hang it in a safe and quiet place outside. And wait for birds to move in.