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问题 选择题

如图是模拟电化学反应装置图．下列说法正确的是（　　）

A．开关K置于N处，则铁电极的电极反应式为：Fe-2e→Fe2+

B．开关K置于N处，可以减缓铁的腐蚀

C．开关K置于M处，则铁电极的电极反应式为：2Cl--2e→Cl2↑

D．开关K置于M处，电子从碳棒经开关K流向铁棒

答案

A．开关K置于N处，该装置是电解池，铁电极是阴极，阴极上得电子发生还原反应，故A错误；

B．开关K置于N处，该装置是电解池，碳棒作阳极，阳极上溶液中阴离子失电子发生氧化反应，铁棒作阴极，铁棒上阳离子得电子发生还原反应，所以可以减缓铁的腐蚀，故B正确；

C．开关K置于M处，该装置是原电池，铁作负极，铁电极的电极反应式为：Fe-2e-→Fe2+，故C错误；

D．开关K置于M处，该装置是原电池，碳棒作正极，铁棒作负极，电子从铁棒沿导线流向碳棒，故D错误；

故选B．

单项选择题

事故情况下，在全站无电后，必须将电容器支路断路器（）。

A、先合上

B、先断开

C、先更换

D、先不动
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单项选择题

In the United States, older people rarely live with their adult children. But in many other cultures children are expected to care (1) their aged parents. In some parts of Italy, the percentage of adult children who (2) with their parents (3) 65 to 70 percent. In Thailand, too, children are expected to take care of their elderly parents; few Thai elderly live (4) . What explains these differences in living arrangements (5) cultures Modernization theory (6) the extended family household to low levels of economic development. In traditional societies, the elderly live with their children in large extended family units for economic reasons. But with modernization, children move to urban areas, leaving old people (7) in (8) rural areas. Yet modernization theory cannot explain why extended family households were never common in the United States or England, or why families in Italy, which is fully modernized, (9) a p tradition of intergenerational living. Clearly, economic development alone cannot explain (10) living arrangements. Another theory associated intergenerational living arrangements with inheritance patterns. In some cultures, the stem family pattern of inheritance (11) . (12) this system, parents live with a married child, usually the oldest son, who then (13) their property when they die. The stem family system was once common in Japan, but changes in inheritance laws, (14) broader social changes brought (15) by industrialization and urbanization, have (16) the (17) .In 1960 about 80 percent of Japanese over 65 lived with their children; by 1990 only 60 percent did-a figure that is still high (18) U.S. standards, but which has been (19) steadily. In Korea, too, traditional living arrangements are (20) : the percentage of aged Koreans who live with a son declined from 77 percent in 1984 to 50 percent just 10 years later. Although most elderly Koreans still expect to live with a son, their adult children do not expect to live with their children when they grow old.

9（）

A.maintain

B.promote

C.reserve

D.support
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