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问题 单项选择题

混凝土的收缩对钢筋混凝土和预应力钢筋混凝土结构构件产生影响，以下叙述中错误的是：（）。

A.会使两端固定的钢筋混凝土梁产生拉应力或裂缝 

B.会使长度较长的钢筋混凝土连续梁、板产生拉应力或裂缝 

C.会使预应力混凝土构件中预应力值增大 

D.会使混凝土结构房屋的竖向构件产生附加的剪力

答案

参考答案：C

解析：

混凝土的收缩会使预应力混凝土构件中预应力损失。

判断题

m阶B-树具有k个后继的非叶子结点含有k-1个键值。
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单项选择题

Ants first captured the attention of software engineers in the early 1990s. A single ant cannot do much on its own, but a group of ants (52) can solve complex problems. That inspired people like Marco Dorigo, who is one of the founders of a (53) known as group intelligence.

Ants are good at choosing the shortest possible route between a food (54) and their nest. This reminds us of a classic computational travelling-salesman problem. Given a list of cities and their (55) apart, the salesman must find the shortest route needed to visit each city once. As the number of cities (56) , the problem gets more complicated.Ants solve their own problem using chemical signals called pheromones (信息素), when an ant finds food, she takes it back to the nest, (57) a pheromone trail that will attract others. The more ants that (58) the trail, the per it becomes. (59) , the pheromones evaporate (挥发) quickly, so once all the food has been collected, the trail soon goes cold. This rapid evaporation means long trails are less (60) than short ones, all else being equal. Pheromones thus turn the (61) intelligence of the individual ants into something more powerful.

61().

A.interrupted 

B.limited 

C.considerable 

D.unreliable
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