单选题 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 stronger 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.

单选题 A. by the way B. as a whole C. for some time D. on the average

单选题 A. field B. profession C. company D. fund

【正确答案】 A

【答案解析】本题测试语义与词汇。field“领域”；profession“职业，同行”；company“公司”；fund“基金”。本题想说的是Marco．Dorigo是“集体智慧”这个领域的创始者之一。故答案为A。

单选题 A. range B. source C. chain D. origin

单选题 A. locations B. positions C. spaces D. distances

单选题 A. changes B. holds C. grows D. decreases

单选题 A. putting aside B. working on C. waiting for D. leaving behind

【正确答案】 D

【答案解析】本题测试词组。题干意思为：当一只蚂蚁找到食物时，她会将其带回自己的巢穴，留下信息素，来引起其他蚂蚁的注意。只有leave behind有“留下”的意思。故选D。