Problem: Unicode:

Unicode includes a mechanism for modifying character shape that greatly extends the supported glyph repertoire. This covers the use of combining diacritical marks. They are inserted after the main character. Multiple combining diacritics may be stacked over the same character. Unicode also contains precomposed versions of most letter/diacritic combinations in normal use. These make conversion to and from legacy encodings simpler, and allow applications to use Unicode as an internal text format without having to implement combining characters. For example, e can be represented in Unicode as U+0065 (LATIN SMALL LETTER E) followed by U+0301 (COMBINING ACUTE ACCENT), but it can also be represented as the precomposed character U+00E9 (LATIN SMALL LETTER E WITH ACUTE). Thus, in many cases, users have multiple ways of encoding the same character. To deal with this, Unicode provides the mechanism of canonical equivalence.

What are inserted before a main character?
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A: unanswerable

Problem: In the United States, heating, ventilation and air conditioning (HVAC) systems account for 30% (4.65 EJ/yr) of the energy used in commercial buildings and nearly 50% (10.1 EJ/yr) of the energy used in residential buildings. Solar heating, cooling and ventilation technologies can be used to offset a portion of this energy.
What percentage of energy in commercial buildings comes from HVAC systems?
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Answer: 50

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Some other popular sights are the Waterloo Column, the Laves House, the Wangenheim Palace, the Lower Saxony State Archives, the Hanover Playhouse, the Kropcke Clock, the Anzeiger Tower Block, the Administration Building of the NORD/LB, the Cupola Hall of the Congress Centre, the Lower Saxony Stock, the Ministry of Finance, the Garten Church, the Luther Church, the Gehry Tower (designed by the American architect Frank O. Gehry), the specially designed Bus Stops, the Opera House, the Central Station, the Maschsee lake and the city forest Eilenriede, which is one of the largest of its kind in Europe. With around 40 parks, forests and gardens, a couple of lakes, two rivers and one canal, Hanover offers a large variety of leisure activities.
Approximately how many gardens are there in Hanover?
A: unanswerable

Context and question: From 1842 onwards, Chopin showed signs of serious illness. After a solo recital in Paris on 21 February 1842, he wrote to Grzymaa: "I have to lie in bed all day long, my mouth and tonsils are aching so much." He was forced by illness to decline a written invitation from Alkan to participate in a repeat performance of the Beethoven Seventh Symphony arrangement at Erard's on 1 March 1843. Late in 1844, Charles Halle visited Chopin and found him "hardly able to move, bent like a half-opened penknife and evidently in great pain", although his spirits returned when he started to play the piano for his visitor. Chopin's health continued to deteriorate, particularly from this time onwards. Modern research suggests that apart from any other illnesses, he may also have suffered from temporal lobe epilepsy.
Chopin wrote in 1842 that he had to lie in bed all day because what ached so much?
Answer: mouth and tonsils

Question: Droney's health was poor and Kerry had decided to run for his position in the 1978 election should Droney drop out. However, Droney was re-elected and his health improved; he went on to re-assume many of the duties that he had delegated to Kerry. Kerry thus decided to leave, departing in 1979 with assistant DA Roanne Sragow to set up their own law firm. Kerry also worked as a commentator for WCVB-TV and co-founded a bakery, Kilvert & Forbes Ltd., with businessman and former Kennedy aide K. Dun Gifford.
Is there an answer to this question: Who did Kerry start a bakery with?

Answer: K. Dun Gifford

PAL consoles face another incompatibility when playing out-of-region cartridges: the NTSC video standard specifies video at 60 Hz while PAL operates at 50 Hz, resulting in approximately 16.7% slower gameplay. Additionally, PAL's higher resolution results in letterboxing of the output image. Some commercial PAL region releases exhibit this same problem and, therefore, can be played in NTSC systems without issue while others will face a 20% speedup if played in an NTSC console. To mostly correct this issue, a switch can be added to place the SNES PPU into a 60 Hz mode supported by most newer PAL televisions. Later games will detect this setting and refuse to run, requiring the switch to be thrown only after the check completes.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What video standard to later games operate at?
Ah, so..
unanswerable