Problem: Glass:

The alkali metal ions are small and mobile; their presence in glass allows a degree of electrical conductivity, especially in molten state or at high temperature. Their mobility decreases the chemical resistance of the glass, allowing leaching by water and facilitating corrosion. Alkaline earth ions, with their two positive charges and requirement for two non-bridging oxygen ions to compensate for their charge, are much less mobile themselves and also hinder diffusion of other ions, especially the alkalis. The most common commercial glasses contain both alkali and alkaline earth ions (usually sodium and calcium), for easier processing and satisfying corrosion resistance. Corrosion resistance of glass can be achieved by dealkalization, removal of the alkali ions from the glass surface by reaction with e.g. sulfur or fluorine compounds. Presence of alkaline metal ions has also detrimental effect to the loss tangent of the glass, and to its electrical resistance; glasses for electronics (sealing, vacuum tubes, lamps...) have to take this in account.

What types of compunds does typical glass have?
---
A: unanswerable

Problem: Manhattan's skyline, with its many skyscrapers, is universally recognized, and the city has been home to several of the tallest buildings in the world. As of 2011, New York City had 5,937 high-rise buildings, of which 550 completed structures were at least 330 feet (100 m) high, both second in the world after Hong Kong, with over 50 completed skyscrapers taller than 656 feet (200 m). These include the Woolworth Building (1913), an early gothic revival skyscraper built with massively scaled gothic detailing.
How many structures in New York City are over 100m tall?
---
Answer: 550

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The 1850 census saw a dramatic shift in the way information about residents was collected. For the first time, free persons were listed individually instead of by head of household. There were two questionnaires: one for free inhabitants and one for slaves. The question on the free inhabitants schedule about color was a column that was to be left blank if a person was white, marked "B" if a person was black, and marked "M" if a person was mulatto. Slaves were listed by owner, and classified by gender and age, not individually, and the question about color was a column that was to be marked with a "B" if the slave was black and an "M" if mulatto.
How were slaves listed in the 1850 US census?
A: by owner

Context and question: Artists such as Gary Numan, the Human League, Soft Cell, John Foxx and Visage helped pioneer a new synthpop style that drew more heavily from electronic and synthesizer music and benefited from the rise of MTV. Post-punk artists such as Scritti Politti's Green Gartside and Josef K's Paul Haig, previously engaged in avant-garde practices, turned away from these approaches and pursued mainstream styles and commercial success. These new developments, in which post-punk artists attempted to bring subversive ideas into the pop mainstream, began to be categorized under the marketing term new pop.
What did some post-punk artists reject their previous avant-garde practices to pursue?
Answer: commercial success

Question: Estonia produces about 75% of its consumed electricity. In 2011 about 85% of it was generated with locally mined oil shale. Alternative energy sources such as wood, peat, and biomass make up approximately 9% of primary energy production. Renewable wind energy was about 6% of total consumption in 2009. Estonia imports petroleum products from western Europe and Russia. Oil shale energy, telecommunications, textiles, chemical products, banking, services, food and fishing, timber, shipbuilding, electronics, and transportation are key sectors of the economy. The ice-free port of Muuga, near Tallinn, is a modern facility featuring good transshipment capability, a high-capacity grain elevator, chill/frozen storage, and new oil tanker off-loading capabilities.[citation needed] The railroad serves as a conduit between the West, Russia, and other points to the East.[citation needed]
Is there an answer to this question: What percentage of electricity was produced with local oil shale in 2011?

Answer: about 85%

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
On 24 March 2009, the Nigerian Federal Ministry of Science and Technology, NigComSat Ltd. and CGWIC signed another contract for the in-orbit delivery of the NigComSat-1R satellite. NigComSat-1R was also a DFH-4 satellite, and the replacement for the failed NigComSat-1 was successfully launched into orbit by China in Xichang on December 19, 2011. The satellite according to then-Nigerian President Goodluck Jonathan which was paid for by the insurance policy on NigComSat-1 which de-orbited in 2009, would have a positive impact on national development in various sectors such as communications, internet services, health, agriculture, environmental protection and national security.
What paid for Nigeria's fourth satellite?
A:
the insurance policy on NigComSat-1