题干

2011年12月5日,环保部制定的《环境空气质量标准》第二次公开征求意见结束,大家普遍赞成将PM2.5(PM2.5是指大气中直径接近于2.5×10 -6m的颗粒物)纳入常规空气质量评价。下列有关PM2.5说法不正确的是

A:PM2.5表面积大能吸附大量的有毒、有害物质

B:PM2.5在空气中形成了气溶胶

C:实施绿化工程,可以有效地防治PM2.5污染

D:研制开发燃料电池汽车,降低机动车尾气污染,某种程度可以减少PM2.5污染

上一题 下一题 0.0难度 选择题 更新时间:2011-11-30 10:08:46

答案(点此获取答案解析)

B

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阅读理解

    China is a big country, and there is no simple answer to the question “When is the best time to visit China? ” There are two best times to visit China, depending on your preference.

    October

    Things to do: hike on the Great Wall, photography tour

    Places to visit: Beijing, Xi'an, Shanghai, Guilin, Jiuzhaigou, Chengdu

The best time to go to China is early autumn (October).

    Most of China has warm temperatures, and the summer rains have stopped (apart from around HongKong and Sanya) so it's pretty dry. The autumnn colours are also amazing. It is quiet at tourist attractions for most of the month, as the summer holiday travel crowds have gone. But try to avoid October 1st -7th, which is the Chinese National Day holiday, as attractions, transport and hotels are packed with Chinese tourists and prices go up a lot.

    Late Spring (April to May)

    Things to do: appreciate flowers, Li River cruise, ethnic festivals

    Places to visit: Beijing, Xi'an, Guilin, Huangshan, GuiZhou, Zhangjiajie

    The second-best time to travel to China is probably in April and May, when the flowers are in bloom and the temperatures are warming up. In late spring, temperatures across China are getting into the 20s (℃), except the extreme northwest and northeast. While the North of China is still dry, the summer rains have already begun in the South. This could actually improve the view in the form of mountain fog in mountainous areas like the Li River and the Yellow Mountains.

    Ethnic festivals in GuiZhou are concentrated in April and May, such as the Sisters' Meal Festival. If you are interested in Miao and Dong ethnic cultures, this is a good time to visit.

    Travel prices are average: cheaper than June to October, but more expensive than the lower season from November to March.