当钻到一口井的水平段时发生井涌并关井。如果溢流在水平段，预期关井立压和关井套压将是多少？（）

A、关井套压为零.

B、关井套压远远大于关井立压

C、关井立压远远大于关井套压.

D、关井立压等于关井套压.

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.

58().

A. follow

B. lead 

C. surround 

D. avoid