皮带运输机打滑的原因是什么？通常有哪些调整方法？

明桥面应在轨道中心铺设步行板并设置单侧或双侧人行道。

[问题1] 什么叫数据库的安全性，它有哪些内容

一旦井塌发生，提高钻井液粘度和切力，适当提高密度，控制低滤失量是重要的处理措施之一。

Part 3

Questions 19-25

·Read the following passage and answer questions 19-25.
·For questions 19-25, choose the correct answer A, B, C and D.
·Mark your answers on the Answer Sheet.
While still in its early stages, welfare reform has already been judged a great success in many states, at least UN is getting people off welfare, lt’s estimated that more than two million have left the roles since 1994.
In the past four years, welfare in rolls in Athens country has been cut in half. But 70 percent of the people who left in the past two years took jobs that paid less than $6 an hour. The result: The Athens country poverty rate still remains at more than 30 percent—twice the national average.
For advocates for the poor, that’s an indication that much more needs to be done.
"More people are getting jobs, but it’s not making their lives any better," says Kathy Lairn, a policy analyst at the center in budget and policy priorities in Washington.
Canter analysis of US census data nationwide found that between 1995 and 1996, a great percentage of single, fame-headed household were earning money on their own, but that average income for these households actually went down.
But for many, the fact that poor people are able to support themselves almost as well without government aid as they did with it is in itself a huge victory.
"Welfare was a poison. It was a toxin that was poisoning the family," says Rector, a welfare reform is changing the moral climate in low-income communities. It’s beginning to rebuild the work ethic, which is much more important.
Mr. Rector and others argued that once "the habit of dependency is cracked," then the country can make other policy changes aimed at improving living standards.

About the welfare reform the author’s attitude is ______.

A．indifferent

B．positive

C．objective

D．critical

测得某溶液的pH值为6.0，该溶液的pOH值为（）。

A.8.0

B.6.0

C.4.0

D.10.0