Problem: Railway electrification system:

A few lines of the Paris Métro in France operate on a four-rail power scheme because they run on rubber tyres which run on a pair of narrow roadways made of steel and, in some places, concrete. Since the tyres do not conduct the return current, the two guide rails provided outside the running 'roadways' double up as conductor rails, so at least electrically it is a four-rail scheme. One of the guide rails is bonded to the return conventional running rails situated inside the roadway so a single polarity supply is required. The trains are designed to operate from either polarity of supply, because some lines use reversing loops at one end, causing the train to be reversed during every complete journey. The loop was originally provided to save the original steam locomotives having to 'run around' the rest of the train saving much time. Today, the driver does not have to change ends at termini provided with such a loop, but the time saving is not so significant as it takes almost as long to drive round the loop as it does to change ends. Many of the original loops have been lost as lines were extended.

What runs on a pair of wide roadways made of steel?
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A: unanswerable


Problem: Simultaneous videoconferencing among three or more remote points is possible by means of a Multipoint Control Unit (MCU). This is a bridge that interconnects calls from several sources (in a similar way to the audio conference call). All parties call the MCU, or the MCU can also call the parties which are going to participate, in sequence. There are MCU bridges for IP and ISDN-based videoconferencing. There are MCUs which are pure software, and others which are a combination of hardware and software. An MCU is characterised according to the number of simultaneous calls it can handle, its ability to conduct transposing of data rates and protocols, and features such as Continuous Presence, in which multiple parties can be seen on-screen at once. MCUs can be stand-alone hardware devices, or they can be embedded into dedicated videoconferencing units.
What feature enables an MCU to allow for multiple parties to be seen on screen at the same time?
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Answer: Continuous Presence


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Iran consists of the Iranian Plateau with the exception of the coasts of the Caspian Sea and Khuzestan Province. It is one of the world's most mountainous countries, its landscape dominated by rugged mountain ranges that separate various basins or plateaux from one another. The populous western part is the most mountainous, with ranges such as the Caucasus, Zagros and Alborz Mountains; the last contains Iran's highest point, Mount Damavand at 5,610 m (18,406 ft), which is also the highest mountain on the Eurasian landmass west of the Hindu Kush.
What is Iran's highest mountain?
A: Mount Damavand


Context and question: Some multiracial individuals feel marginalized by U.S. society. For example, when applying to schools or for a job, or when taking standardized tests, Americans are sometimes asked to check boxes corresponding to race or ethnicity. Typically, about five race choices are given, with the instruction to "check only one." While some surveys offer an "other" box, this choice groups together individuals of many different multiracial types (ex: European Americans/African-Americans are grouped with Asian/Native American Indians).
What does the "other" box avoid?
Answer: unanswerable


Question: Mendes revealed that production would begin on 8 December 2014 at Pinewood Studios, with filming taking seven months. Mendes also confirmed several filming locations, including London, Mexico City and Rome. Van Hoytema shot the film on Kodak 35 mm film stock. Early filming took place at Pinewood Studios, and around London, with scenes variously featuring Craig and Harris at Bond's flat, and Craig and Kinnear travelling down the River Thames.
Is there an answer to this question: Where did initial shoots for the film take place?

Answer: Pinewood Studios


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
In 1986, CBS sold its music publishing arm, CBS Songs, to Stephen Swid, Martin Bandier, and Charles Koppelman for $125 million making it the foundation of their SBK Entertainment.
ABC Songs was sold to whom?
A:
unanswerable