“三同时”制度的概念和意义？

低压压力容器的压力表（）等级应不低于2.5级。

A.力度

B.垂度

C.精度

D.密度

有水塔和无水塔的管网，二级泵站计算流量的差别在于______。
(1)无水塔：二级泵站供水量等于用水量，满足最高时用水要求，其他时(非最高时)多台水泵大小搭配，使得在高效范围内运行。
(2)有水塔：水塔能调节供水和用水之间的流量关系，二级泵站供水量不等于用水量，二级泵站多级供水(一般不大于3级)。
(3)无水塔：水塔能调节供水和用水之间的流量关系，二级泵站供水量不等于用水量，二级泵站多级供水(一般不大于3级)。
(4)有水塔：二级泵站供水量等于用水量，满足最高时用水要求，其他时(非最高时)多台水泵大小搭配，使得在高效范围内运行。

A．(1)、(2)
B．(3)、(4)
C．(1)、(4)
D．(2)、(3)

i5T5.4智能车床两轴进给电机额定功率是多少？

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.

52().

A. by the way

B. as a whole

C. for some time

D. on the average

DOS操作系统的功能主要是对文件和设备进行（）。

A.操作

B.管理

C.打印

D.通信