Problem: Please answer a question about the following article about Computer:
The abacus was initially used for arithmetic tasks. The Roman abacus was used in Babylonia as early as 2400 BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval European counting house, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money.
A checkered cloth on a table was used in medieval Europe to help count what?
A: sums of money
Problem: Please answer a question about the following article about Light-emitting diode:
Because of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs for their rear light clusters. The use in brakes improves safety, due to a great reduction in the time needed to light fully, or faster rise time, up to 0.5 second faster[citation needed] than an incandescent bulb. This gives drivers behind more time to react. In a dual intensity circuit (rear markers and brakes) if the LEDs are not pulsed at a fast enough frequency, they can create a phantom array, where ghost images of the LED will appear if the eyes quickly scan across the array. White LED headlamps are starting to be used. Using LEDs has styling advantages because LEDs can form much thinner lights than incandescent lamps with parabolic reflectors.
Why are LED lights sought after for various applications?
A: their long life
Problem: Please answer a question about the following article about Geography of the United States:
The capital city, Washington, District of Columbia, is a federal district located on land donated by the state of Maryland. (Virginia had also donated land, but it was returned in 1849.) The United States also has overseas territories with varying levels of independence and organization: in the Caribbean the territories of Puerto Rico and the U.S. Virgin Islands, and in the Pacific the inhabited territories of Guam, American Samoa, and the Northern Mariana Islands, along with a number of uninhabited island territories.
What is the capital city of the US?
A: Washington, District of Columbia
Problem: Please answer a question about the following article about 2008 Summer Olympics torch relay:
 Greece: On March 24, 2008, the Olympic Flame was ignited at Olympia, Greece, site of the ancient Olympic Games. The actress Maria Nafpliotou, in the role of a High Priestess, ignited the torch of the first torchbearer, a silver medalist of the 2004 Summer Olympics in taekwondo Alexandros Nikolaidis from Greece, who handed the flame over to the second torchbearer, Olympic champion in women's breaststroke Luo Xuejuan from China. Following the recent unrest in Tibet, three members of Reporters Without Borders, including Robert Ménard, breached security and attempted to disrupt a speech by Liu Qi, the head of Beijing's Olympic organising committee during the torch lighting ceremony in Olympia, Greece. The People's Republic of China called this a "disgraceful" attempt to sabotage the Olympics. On March 30, 2008 in Athens, during ceremonies marking the handing over of the torch from Greek officials to organizers of the Beijing games, demonstrators shouted 'Free Tibet' and unfurled banners; some 10 of the 15 protesters were taken into police detention. After the hand-off, protests continued internationally, with particularly violent confrontations with police in Nepal.
What place had police experience violent problems with protesters?
A:
Nepal.