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问题 填空题

一个梯形的下底是上底的3倍，如果将上底延长6厘米，就成了一个平行四边形，这个梯形的上底是______厘米，下底是______厘米．

答案

上底：6÷（3-1）=3（厘米）；

下底：3×3=9（厘米）；

答：这个梯形的上底是3厘米，下底是9厘米；

故答案为：3，9．

读图填空题

两只黑猫交配后产生了四只不同毛色的小猫，情况如图所示。请回答下列问题

（1）猫毛色的棕色与黑色是同一性状的不同表现形式，在遗传学上称为      性状。

（2）由图解可以推出猫的棕色为         性状。

（3）若控制猫毛色的基因分别用A、a表示，那么亲代黑色猫的基因组成是    ，子代棕色猫的基因组成是          。

（4）若亲代猫的体细胞染色体数目是n对，则子代猫的体细胞染色体数目是      对。
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单项选择题

The history of African—Americans during the past 400 years is traditionally narrated (1) an ongoing struggle against (2) and indifference on the part of the American mainstream, and a struggle (3) as an upward movement is (4) toward ever more justice and opportunity.

Technology in and of (5) is not at fault; it’s much too simple to say that gunpowder or agricultural machinery or fiber optics (6) been the enemy of an (7) group of people. A certain machine is put (8) work in a certain way—the purpose (9) which it was designed. The people who design the machines are not intent on unleashing chaos; they are usually trying to (10) a task more quickly, cleanly, or cheaply, (11) the imperative of innovation and efficiency that has ruled Western civilization (12) the Renaissance.

Mastery of technology is second only (13) money as the true measure of accomplishment in this country, and it is very likely that by (14) this under-representation in the technological realm, and by not questioning and examining the folkways that have (15) it, blacks are allowing. (16) to be kept out of the mainstream once again. This time, however, they will be (17) from the greatest cash engine of the twenty-first century. Inner-city blacks in particular are in danger, and the beautiful suburbs (18) ring the decay of Hartford, shed the past and learn to exist without contemplating or encountering the tragedy of the inner city.

And blacks must change as well. The ways that (19) their ancestors through captivity and coming to freedom have begun to loose their utility. If blacks (20) to survive as full participants in this society, they have to understand what works now.

3（）

A.charting

B.charts

C.charted

D.tochart
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