Problem: Punjab, Pakistan:

Punjab during Mahabharata times was known as Panchanada. Punjab was part of the Indus Valley Civilization, more than 4000 years ago. The main site in Punjab was the city of Harrapa. The Indus Valley Civilization spanned much of what is today Pakistan and eventually evolved into the Indo-Aryan civilisation. The Vedic civilisation flourished along the length of the Indus River. This civilisation shaped subsequent cultures in South Asia and Afghanistan. Although the archaeological site at Harappa was partially damaged in 1857 when engineers constructing the Lahore-Multan railroad used brick from the Harappa ruins for track ballast, an abundance of artefacts have nevertheless been found. Punjab was part of the great ancient empires including the Gandhara Mahajanapadas, Achaemenids, Macedonians, Mauryas, Kushans, Guptas, and Hindu Shahi. It also comprised the Gujar empire for a period of time, otherwise known as the Gurjara-Pratihara empire. Agriculture flourished and trading cities (such as Multan and Lahore) grew in wealth.

When was the archaeological site at Harappa discovered?
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A: unanswerable

Problem: In the UK, the London, Brighton and South Coast Railway pioneered overhead electrification of its suburban lines in London, London Bridge to Victoria being opened to traffic on 1 December 1909. Victoria to Crystal Palace via Balham and West Norwood opened in May 1911. Peckham Rye to West Norwood opened in June 1912. Further extensions were not made owing to the First World War. Two lines opened in 1925 under the Southern Railway serving Coulsdon North and Sutton railway station. The lines were electrified at 6.7 kV 25 Hz. It was announced in 1926 that all lines were to be converted to DC third rail and the last overhead electric service ran in September 1929.
When did the UK pioneer overhead electrification of its urban lines?
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Answer: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
London's first and only cable car, known as the Emirates Air Line, opened in June 2012. Crossing the River Thames, linking Greenwich Peninsula and the Royal Docks in the east of the city, the cable car is integrated with London's Oyster Card ticketing system, although special fares are charged. Costing 60 million to build, it carries over 3,500 passengers every day, although this is very much lower than its capacity. Similar to the Santander Cycles bike hire scheme, the cable car is sponsored in a 10-year deal by the airline Emirates.
What was the approximate cost to build the Emirates Airline Cable Car?
A: 60

Context and question: In 2006 Apple presented a special edition for iPod 5G of Irish rock band U2. Like its predecessor, this iPod has engraved the signatures of the four members of the band on its back, but this one was the first time the company changed the colour of the metal (not silver but black). This iPod was only available with 30GB of storage capacity. The special edition entitled purchasers to an exclusive video with 33 minutes of interviews and performance by U2, downloadable from the iTunes Store.
What color was the special U2 iPod model?
Answer: black

Question: Off-grid PV systems have traditionally used rechargeable batteries to store excess electricity. With grid-tied systems, excess electricity can be sent to the transmission grid, while standard grid electricity can be used to meet shortfalls. Net metering programs give household systems a credit for any electricity they deliver to the grid. This is handled by 'rolling back' the meter whenever the home produces more electricity than it consumes. If the net electricity use is below zero, the utility then rolls over the kilowatt hour credit to the next month. Other approaches involve the use of two meters, to measure electricity consumed vs. electricity produced. This is less common due to the increased installation cost of the second meter. Most standard meters accurately measure in both directions, making a second meter unnecessary.
Is there an answer to this question: Why is a second meter usually unnecessary to monitor electricity use?

Answer: Most standard meters accurately measure in both directions

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
At the same time, the political party reached its modern form, with a membership disciplined through the use of a party whip and the implementation of efficient structures of control. The Home Rule League Party, campaigning for Home Rule for Ireland in the British Parliament was fundamentally changed by the great Irish political leader Charles Stewart Parnell in the 1880s. In 1882, he changed his party's name to the Irish Parliamentary Party and created a well-organized grass roots structure, introducing membership to replace "ad hoc" informal groupings. He created a new selection procedure to ensure the professional selection of party candidates committed to taking their seats, and in 1884 he imposed a firm 'party pledge' which obliged MPs to vote as a bloc in parliament on all occasions. The creation of a strict party whip and a formal party structure was unique at the time. His party's efficient structure and control contrasted with the loose rules and flexible informality found in the main British parties; they soon came to model themselves on the Parnellite model.
Did the Irish Parliamentary Party ever adopt the Parnellite model?
A:
they soon came to model themselves on the Parnellite model.