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问题 填空题

6张正面朝下的扑克牌，其中有且只有2张老K，任取2张翻开，2张牌中至少有一张是老K的概率是______，两张牌中没有一张是老K的概率是______．

答案

把这6张牌用1到6这些数字编号，并且假定5号牌和6号牌就是那两张老K．列出从6张牌中取出两张的所有不同组合，总共有15种这样的组合：

1-2，2-3，3-4，4-5，5-6

1-3，2-4，3-5，4-6

1-4，2-5，3-6

1-5，2-6

1-6

注意在这15对牌中有9对包含老K（5号牌和6号牌）．两张牌中没有l张是老K的有6种情况，

故：张牌中至少有一张是老K的概率是：

9
15
=
3
5
；两张牌中没有一张是老K的概率：
6
15
=
2
5
．

故答案为：

3
5
，
2
5
．

选择题

下列图标中，装运浓硫酸的箱子应贴的图标是    

A                 B                C                  D
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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7处填上正确答案（）

A.organizations

B.organisms

C.humans

D.children
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