Problem: Please answer a question about the following article about Police:
Historical studies reveal that policing agents have undertaken a variety of cross-border police missions for many years (Deflem, 2002). For example, in the 19th century a number of European policing agencies undertook cross-border surveillance because of concerns about anarchist agitators and other political radicals. A notable example of this was the occasional surveillance by Prussian police of Karl Marx during the years he remained resident in London. The interests of public police agencies in cross-border co-operation in the control of political radicalism and ordinary law crime were primarily initiated in Europe, which eventually led to the establishment of Interpol before the Second World War. There are also many interesting examples of cross-border policing under private auspices and by municipal police forces that date back to the 19th century (Nadelmann, 1993). It has been established that modern policing has transgressed national boundaries from time to time almost from its inception. It is also generally agreed that in the post–Cold War era this type of practice became more significant and frequent (Sheptycki, 2000).
In what era did cross-border policing increase?
A: post–Cold War
Problem: Please answer a question about the following article about Beer:
The first step, where the wort is prepared by mixing the starch source (normally malted barley) with hot water, is known as "mashing". Hot water (known as "liquor" in brewing terms) is mixed with crushed malt or malts (known as "grist") in a mash tun. The mashing process takes around 1 to 2 hours, during which the starches are converted to sugars, and then the sweet wort is drained off the grains. The grains are now washed in a process known as "sparging". This washing allows the brewer to gather as much of the fermentable liquid from the grains as possible. The process of filtering the spent grain from the wort and sparge water is called wort separation. The traditional process for wort separation is lautering, in which the grain bed itself serves as the filter medium. Some modern breweries prefer the use of filter frames which allow a more finely ground grist.
How long does the mashing step in the brewing process last?
A: 1 to 2 hours
Problem: Please answer a question about the following article about Somerset:
Population growth is higher than the national average, with a 6.4% increase, in the Somerset County Council area, since 1991, and a 17% increase since 1981. The population density is 1.4 persons per hectare, which can be compared to 2.07 persons per hectare for the South West region. Within the county, population density ranges 0.5 in West Somerset to 2.2 persons per hectare in Taunton Deane. The percentage of the population who are economically active is higher than the regional and national average, and the unemployment rate is lower than the regional and national average.
What is the population growth rate of Somerset county 
A: Population growth is higher than the national average, with a 6.4% increase, in the Somerset County Council area, since 1991, and a 17% increase since 1981
Problem: Please answer a question about the following article about Electric motor:
Many of the limitations of the classic commutator DC motor are due to the need for brushes to press against the commutator. This creates friction. Sparks are created by the brushes making and breaking circuits through the rotor coils as the brushes cross the insulating gaps between commutator sections. Depending on the commutator design, this may include the brushes shorting together adjacent sections – and hence coil ends – momentarily while crossing the gaps. Furthermore, the inductance of the rotor coils causes the voltage across each to rise when its circuit is opened, increasing the sparking of the brushes. This sparking limits the maximum speed of the machine, as too-rapid sparking will overheat, erode, or even melt the commutator. The current density per unit area of the brushes, in combination with their resistivity, limits the output of the motor. The making and breaking of electric contact also generates electrical noise; sparking generates RFI. Brushes eventually wear out and require replacement, and the commutator itself is subject to wear and maintenance (on larger motors) or replacement (on small motors). The commutator assembly on a large motor is a costly element, requiring precision assembly of many parts. On small motors, the commutator is usually permanently integrated into the rotor, so replacing it usually requires replacing the whole rotor.
How is RFI generated?
A:
sparking