Problem: Punjab, Pakistan:

The province is home to several historical sites, including the Shalimar Gardens, the Lahore Fort, the Badshahi Mosque, the Rohtas Fort and the ruins of the ancient city of Harrapa. The Anarkali Market and Jahangir's Tomb are prominent in the city of Lahore as is the Lahore Museum, while the ancient city of Taxila in the northwest was once a major centre of Buddhist and Hindu influence. Several important Sikh shrines are in the province, including the birthplace of the first Guru, Guru Nanak. (born at Nankana Sahib). There are a few famous hill stations, including Murree, Bhurban, Patriata and Fort Munro.

What city is the Murree hill nearby?
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A: unanswerable


Problem: Beyoncé participated in George Clooney and Wyclef Jean's Hope for Haiti Now: A Global Benefit for Earthquake Relief telethon and was named the official face of the limited edition CFDA "Fashion For Haiti" T-shirt, made by Theory which raised a total of $1 million. On March 5, 2010, Beyoncé and her mother Tina opened the Beyoncé Cosmetology Center at the Brooklyn Phoenix House, offering a seven-month cosmetology training course for men and women. In April 2011, Beyoncé joined forces with US First Lady Michelle Obama and the National Association of Broadcasters Education Foundation, to help boost the latter's campaign against child obesity by reworking her single "Get Me Bodied". Following the death of Osama bin Laden, Beyoncé released her cover of the Lee Greenwood song "God Bless the USA", as a charity single to help raise funds for the New York Police and Fire Widows' and Children's Benefit Fund.
What enterprise did Beyonce and her mother start on March 5, 2010?
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Answer: Beyoncé Cosmetology Center at the Brooklyn Phoenix House


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
On April 17, 1946, the Kaliningrad Oblast — the northern portion of the former German province of East Prussia—was annexed by the Soviet Union and made part of the Russian SFSR.
On what date was Kaliningrad Oblast annexed?
A: April 17, 1946


Context and question: The Portuguese language is the official national language and the primary language taught in schools. English and Spanish are also part of the official curriculum. The city has six international schools: American School of Brasília, Brasília International School (BIS), Escola das Nações, Swiss International School (SIS), Lycée français François-Mitterrand (LfFM) and Maple Bear Canadian School. August 2016 will see the opening of a new international school - The British School of Brasilia. Brasília has two universities, three university centers, and many private colleges.
What languages besides Portuguese are taught in Brasilia's schools?
Answer: English and Spanish


Question: The hole walls for boards with two or more layers can be made conductive and then electroplated with copper to form plated-through holes.  These holes electrically connect the conducting layers of the PCB. For multi-layer boards, those with three layers or more, drilling typically produces a smear of the high temperature decomposition products of bonding agent in the laminate system. Before the holes can be plated through, this smear must be removed by a chemical de-smear process, or by plasma-etch. The de-smear process ensures that a good connection is made to the copper layers when the hole is plated through. On high reliability boards a process called etch-back is performed chemically with a potassium permanganate based etchant or plasma. The etch-back removes resin and the glass fibers so that the copper layers extend into the hole and as the hole is plated become integral with the deposited copper.
Is there an answer to this question: What process does a multi-layer PCB usually undergo before plating to make sure the layers have good connectivity with each other?

Answer: de-smear


One of the Han's greatest mathematical advancements was the world's first use of negative numbers. Negative numbers first appeared in the Nine Chapters on the Mathematical Art as black counting rods, where positive numbers were represented by red counting rods. Negative numbers are used in the Bakhshali manuscript of ancient India, but its exact date of compilation is unknown. Negative numbers were also used by the Greek mathematician Diophantus in about 275 AD, but were not widely accepted in Europe until the 16th century AD.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): In what treatise did negative numbers first appear?
Ah, so..
the Nine Chapters on the Mathematical Art