下列对安全生产的意义的叙述哪些是正确的？（）A．安全生产关系到人民群众生命和财产安全

B

America has long been considered the land of opportunity(机遇)by those from other countries. Americans, too, believe that the United States gives almost limitless opportunities for those who want to open business on their own.

Today, Americans are still fond of trying their hand at becoming small business people, even though only one out of two survives in the first two years. Many of these people start their business for the wrong reason; to get away from the paper work of their present jobs or to exchange the responsibility(责任) of their present jobs for freer life styles. But more, not less paper work and responsibility come with the ownership of a small business.

Not all small businesses succeed. Fifty percent of the 4 550 000 that start in the United States ever fail. Still ninety-five percent of businesses in the U.S. can be regarded as small, and these businesses altogether produce forty percent of America’s total national products.

60．According to the passage, which of the following statements is true?

A．People from other countries and Americans think there are a lot of opportunities in the U.S.

B．Only the Americans think the U.S. can give them many opportunities.

C．Both people from other countries and Americans believe they have many opportunities in the U.S so that they can do whatever they like.

D．People from other countries and Americans all think the U.S. the place where they can realize their dreams.

61．From this passage, we know that________.

A．many people from other countries think that in the past there were many opportunities in the U.S. but not now

B．now Americans don’t believe the U.S. can give them a lot of opportunities

C．people from other countries still think they have more opportunities in the U.S. than in their own countries

D．Americans think they have more opportunities to start their own business than those from other countries

62．According to this passage, many American people like to start their own business because___.

A．they want to become rich soon

B．they not only dislike their present jobs but also want a freer life style

C．they don’t want to do paper work

D．they want to have more chances

63．From this passage, we can get the idea that________.

A．it is easy to do business successfully in the U.S

B．it is easy to start a business but hard to make it successful

C．there are more big business than small business in the U.S

D．only big business can succeed in the U.S

天津某企业于1989年12月派业务员郑某到常州市购买麻袋5万条，并携带部分货款。郑某在火车上认识了上海某机械厂的业务员杜某，在交谈中得知他厂有一机械设备是本厂急需用的、且价格便宜。于是，郑业务员就随杜、业务员到上海某机械厂同该厂订立口头购销合同，预购了一台设备，并交付2万元定金。之后，郑业务员给本厂厂长打电话，告知购买设备一事，无钱购买麻袋，速寄款以便购买麻袋。厂长接到电话后，指责郑业务员不应购买设备，让其速退货，索回定金。
上海某机械厂不予退还定金，要求履行合同。为此双方发生纠纷，上海某机械厂诉诸法院。在法庭上，天津某企业厂长答辩说：我厂只让郑业务员购买麻袋，未让其购买设备，对此纠纷，我厂不负任何责任。
问题：
(1)购买设备的口头合同是否为有效合同并说明理由。
(2)定金是否应当返还为什么
(3)本案谁有过错怎样承担责任

在生产工艺技术比选时，在调查研究国内外设备生产、制造、供应、运行状况的基础上，对拟选的主要设备做多方案比选时，往往重点进行( )比选。

A．引进和国产设备

B．原料路线

C．投资费用

D．运营费用

土壤含水率在5%以上，（）以内称为潮土。

A、20%

B、25%

C、30%

D、35%

教育发展水平的最终决定性因素是（）。

A.生产力

B.生产关系

C.经济基础

D.政治制度