在进站道岔外方线路上施工时，对区间方面，以关闭的（）进行防护。

典型的纯风险包括（）。

A.价格变动

B.地震

C.汇率变动

D.洪水

E.战争

我国公文管理自动化的背景与动力是什么

阅读理解。

     阅读下面短文,根据所读内容在文后第76-85小题的空格里填上适当的单词或短语。

注意：每空不超过3个单词。 

     The best thing you can say about the roofs of most city buildings is that you don't have to look at them.

That's very good, since an urban landscape viewed from above can be an unlovely thing-block after block

of tarred (铺有沥青的) black rooftops, sticky in summer, ugly year-round. Or at least that's the way it used

to be.

     But urban roofs are going green. Environmental designers have begun to realize that the tops of buildings

don't have to be wastelands. Indeed, they can be gardens, planted with grasses, flowers and bushes.

     A planted roof usually comes in one of two varieties: extensive or intensive. The extensive type is wide

and shallow, with a soil depth of less than 8 inches, able to support smaller plants. The intensive type may

be smaller, but it's relatively deeper and home to larger plants. Whatever the design, green roofs are not so

simple as ordinary gardens. The have multiple layers beneath the soil, including a drainage layer, waterproofing,

structural support, and so on. But this system can do a great deal of good. A recent paper in the journal Bio

Science tells that green roofs can control temperature, contain water and clean the air. And most impressively,

they can cut heat loss from a building by 50%, lower air-conditioning costs by 25%, and reduce the

urban-heated-island effect by 2℃.

     Of course, apart from the square feet greened and heat reduced, green roofs are even more valued since

people can gain some psychological comfort simply by having a quiet place to go. as so often happens, what's

good for the planet can also be good for the spirit.

如何进行自动主汽门的严密性试验？

液压支架的侧推装置由（）组成。

A.侧推千斤顶

B.弹簧筒

C.侧护板

D.导向杆

E.锁紧销