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问题 问答题

下图所示的是A、B、C三种溶液两两混合时产生的实验现象，其中A是初中化学常见的酸，请写出符合实验现象的一组物质：

A______B______

C______．

答案

A、B、C三种溶液的现象可知，三种物质发生的是复分解反应，A是酸，A和C反应无现象，所以C是碱，B就是盐，假设A是盐酸，B是可溶性碳酸盐，C是氢氧化钡或者可溶性钡盐，盐酸和碳酸盐反应生成二氧化碳气体，盐酸和氢氧化钡或者钡盐发生反应无明显现象，碳酸盐和氢氧化钡或者可溶性钡盐反应生成白色的碳酸钡沉淀，满足题中的现象．

故答案为：盐酸、碳酸钠（碳酸钾等可溶性碳酸盐均可，但是当C为碱时就不能为碳酸铵）、氢氧化钡（或者可溶性的硝酸钡、氯化钡等，但是B为碳酸铵时本空不能是氢氧化钡）．

单项选择题

An Indian anthropologist, Chandra Thapar, made a study of foreign cultures, which had customs similar to (91) of his native land. One culture in (92) fascinated him because it reveres one animal (93) sacred, much as the people in India (94) the cow. The things he discovered might interest you (95) you will be studying India as part of this course.
The tribe Dr. Thapar (96) is called the Asu and is found on the American continent north of the Tamhumara of Mexico. Though it seems to be a (97) developed society of its type, it has an overwhelming (98) with the care and feeding of the rac—an animal much like a bull in size, strength and temperament. In the Asu tribe, it is almost a social (99) to own at least one (100) not more rats. People not possessing at least one are (101) in low esteem by the community because they are too poor to (102) one of these beasts properly. Some members of the tribe, to (103) their wealth and social prestige, even own (104) of racs.
(105) the rac breed is not very healthy and usually does not live more than five to seven years. Each family invests large (106) of money each year to keep its rac healthy and shod, for it has a tendency to throw its shoes often. There are rac (107) in each community, perhaps more than one if the community is particularly (108) . These specialists, however, due to the long period of ritual training they must undergo and (109) the difficulty of obtaining the right selection of charms to treat the rac, demand (110) offerings whenever a family must treat an ailing rac.

A．as

B．if

C．with

D．when
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问答题 简答题

我国在20世纪80年代中期自营勘探发现的海上最大油田是哪个？
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