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问题 选择题

由①CaCO3、②KI、③Al(OH)3、④AgOH(Ag2O)、⑤I2五种物质所组成的混合物,要使其每种成分逐一溶解（一次只溶解一种物质），试剂选用顺序正确的是  

A．氨水乙醇水氢氧化钾硝酸

B．四氯化碳水氨水氢氧化钠盐酸

C．水苯氨水氢氧化钾硝酸

D．水盐酸氢氧化钠氨水乙醇

答案

答案：B

碘易溶在有机溶剂中，因此首先用四氯化碳溶解碘；碳酸钙不溶于水，氢氧化银钠溶解在氨水中，而氢氧化铝不能，但氢氧化铝钠溶解在氢氧化钾中，所以正确的答案选B。

单项选择题

男性，30岁，患十二指肠溃疡4年，突发上腹剧痛5小时，继而全腹痛、大汗。查体：全腹压痛、反跳痛。考虑有溃疡病穿孔的可能。

十二指肠溃疡穿孔在哪一部位多见( )

A．前壁

B．后壁

C．上壁

D．下壁

E．球后
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单项选择题 案例分析题

From childhood to old age, we all use language as a means of broadening our knowledge of ourselves and the world about us. When humans first 1 , they were like newborn children, unable to use this 2 tool. Yet once language developed, the possibilities for human kind’s future 3 and cultural growth increased.

Many linguists believe that evolution is 4 for our ability to produce and use language. They 5 that our highly evolved brain provides us 6 an innate language ability not found in lower 7 . Proponents of this innateness theory say that our 8 for language is inborn, but that language itself develops gradually, 9 a function of the growth of the brain during childhood. Therefore there are critical 10 times for language development.

Current 11 of innateness theory are mixed, however, evidence supporting the existence of some innate abilities is undeniable. 12 , more and more schools are discovering that foreign languages are best taught in 13 grades. Young children often can learn several languages by being 14 to them, while adults have a much harder time learning another language once the 15 of their first language have become firmly fixed.

16 some aspects of language are undeniably innate, language does not develop automatically in a vacuum. Children who have been 17 from other human beings do not possess language. This demonstrates that 18 with other human beings is necessary for proper language development. Some linguists believe that this is even more basic to human language 19 than any innate capacities. These theorists view language as imitative, learned behavior. 20 , children learn language from their parents by imitating them. Parents gradually shape their child's language skills by positively reinforcing precise imitations and negatively reinforcing imprecise ones.

请在15处填上正确答案（）

A.regulations

B.formations

C.rules

D.constitutions
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