问题 问答题 简答题

什么是矿井通风方法?通常有哪几种?其特点或应用情况是怎样的?

答案

参考答案:

矿井通风方法是指矿井通风机的工作方法,通常有压入式,抽出式和压入抽出联合式几种。

我国部分矿井采用抽放式,它具有井下风流处于负压状态,若因某种原因通风机停止运转时,井下压力升高,不利于瓦斯的涌出,安全性好等优点。压入式多用于开采浅、小窑分布广的低瓦斯矿井,故现在采用的不多。压入抽出联合式能产生较大的通风压力,但通风管理困难,仅用于个别矿井的延深或低瓦斯矿井的改造,新建矿井或高瓦斯矿井不适采用。

单项选择题

The days of elderly women doing nothing but cooking huge meals on holidays are gone. Enter the Red Hat Society--a group holding the belief that old ladies should have fun.

"My grandmothers didn’ t do anything but keep house and serve everybody. They were programmed to do that," said Emily Cornette, head of a chapter of the 7-year-old Red Hat Society.

While men have long spent their time fishing and playing golf, women have sometimes seemed to become unnoticed as they age. But the generation now turning 50 is the baby boomers(生育高峰期出生的人), and the same people who refused their parents’ way of being young are now trying a new way of growing old.

If you take into consideration feminism(女权主义), a bit of spare money, and better health for most elderly, the Red Hat Society looks almost inevitable(必然的). In this society, women over 50 wear red hats and purple(紫色的) clothes, while the women under 50 wear pink hats and light purple clothing.

"The organization took the idea from a poem by Jenny Joseph that begins: When I am an old woman, I shall wear purple. With a red hat which doesn’ t go," said Ellen Cooper, who founded the Red Hat Society in 1998. When the ladies started to wear the red hats, they attracted lots of attention.

"The point of this is that we need a rest from always doing something for someone else," Cooper said, "Women feel so ashamed and sorry when they do something for themselves. " This is why chapters are discouraged from raising money or doing anything useful. "We’ re a ladies’ play group. It couldn’ t be more simple," added Cooper’ s assistant Joe Heywood.

Women join the Red Hat Society because()

A. they want to stay young

B. they would like to appear more attractive

C. they would like to have fun and live for themselves

D. they want to be more like their parents

单项选择题