按照企业参与的方式分类,B to B电子商务分为综合式B to B网站、行业型B t

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问题:

按照企业参与的方式分类,B to B电子商务分为综合式B to B网站、行业型B to B网站和( )

A.交易型B to B网站

B.协作型B to B网站

C.行业门户网站

D.企业门户网站

考点:自学考试高等教育自学考试全国2011年10月自学考试电子商务与电子政务试题
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给加粗的字选择正确的读音,打“√”。

棘(jīn   jīng)    雷(fōng   fēng)    黑白相(jiān   jiàn)  

拥(chù   cù)    起(xiān   xīn)      在家里(dāi   dài)

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如图所示,A物块以速度v沿竖直杆匀速下滑,经细绳通过定滑轮拉动物块B在水平方向上运动.当细绳与水平面夹角为θ时,求物块B运动的速度大小.

题型:单项选择题

A.战国曾侯乙墓的青铜编钟(距今约2400年)

B.马家窑文化遗址的粟(距今约5300年)

C.秦始皇兵马俑(距今约2200年)

D.元谋人的门齿(距今约170万年)

题型:单项选择题

在铣床上加工齿轮,主要适用于精度要求不高的单件和小批量生产,其中尤以加工()较多。

A.直齿圆柱齿轮

B.斜齿圆柱齿轮

C.直齿锥齿轮

D.斜齿锥齿轮

题型:单项选择题

Immigrants are consumers as well as producers, so they create jobs as well as taking them. And the work they do need not be at the expense of native workers. Immigrants often hold jobs that natives are unwilling to accept at any feasible wage.

Also, immigrants sometimes help to keep industries viable (能存活的) that would otherwise disappear altogether, causing employment to fall. This was the conclusion of a study of the Los Angeles garment industry in the 1970s and 1980s. And when immigrants working for low wages do put downward pressure on natives’ wages, they may raise the (real) wages of natives in general by keeping prices lower than they otherwise would be.

In theory, then, the net effect of immigration on native wages is uncertain. Unfortunately, most of the empirical (经验主义的) research on whether immigrants make natives worse off in practice is also inconclusive except the effect, one way or the other, seems small. Most of this research has been done in America: if there were any marked influence on wages, that is where you would expect to find it, given the scale of immigration and the tendency of the newcomers to concentrate in certain areas. But most studies have compared wages and employment in areas with many immigrants to wages and employment in areas with few. For instance, one examined the impact of sudden and notorious inflow of refugees to Miami from the Cuban port of Mariel in 1980. Within the space of a few months, 125000 people had arrived, increasing Miami’s labor force by 7%. Yet the study concluded that wages and employment among the city’s natives, including the unskilled, were virtually unaffected. Another study examined the effect of immigration on wages and employment of those at the bottom of the jobs ladder-unskilled blacks and Hispanics. It found that a doubling of the rate of immigration had no detectable effect on natives.

The most recent work, admittedly, has tended to question these findings. Using more detailed statistics and more sophisticated methods than the earlier studies, this work has tended to find that immigrants’ wages take longer to rise to the level of the natives’ wages than has been supposed. This implies a more persistent downward pressure on the host economy’s labor market.

Typically these studies find that immigration does depress unskilled natives’ wages to a small extent. But nearly all economists would agree that the effects of immigration are insignificant in relation to other influences.

According to the Los Angeles study, immigrants ().

A. sometimes help to maintain the existence of some industries

B. sometimes cause employment to fall

C. may lower the wages of natives in general

D. may help promote inflation

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