Problem: Association football:

A number of players may be replaced by substitutes during the course of the game. The maximum number of substitutions permitted in most competitive international and domestic league games is three, though the permitted number may vary in other competitions or in friendly matches. Common reasons for a substitution include injury, tiredness, ineffectiveness, a tactical switch, or timewasting at the end of a finely poised game. In standard adult matches, a player who has been substituted may not take further part in a match. IFAB recommends "that a match should not continue if there are fewer than seven players in either team." Any decision regarding points awarded for abandoned games is left to the individual football associations.

What is one who replaces a player during a game called?
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A: substitutes

Problem: On 9 February 2014, Swiss voters narrowly approved by 50.3% a ballot initiative launched by the national conservative Swiss People's Party (SVP/UDC) to restrict immigration, and thus reintroducing a quota system on the influx of foreigners. This initiative was mostly backed by rural (57.6% approvals), suburban (51.2% approvals), and isolated cities (51.3% approvals) of Switzerland as well as by a strong majority (69.2% approval) in the canton of Ticino, while metropolitan centres (58.5% rejection) and the French-speaking part (58.5% rejection) of Switzerland rather rejected it. Some news commentators claim that this proposal de facto contradicts the bilateral agreements on the free movement of persons from these respective countries.
Which centres of Switzerland mostly rejected the quota system for foreigners?
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Answer: metropolitan

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Antibiotics are screened for any negative effects on humans or other mammals before approval for clinical use, and are usually considered safe and most are well tolerated. However, some antibiotics have been associated with a range of adverse side effects. Side-effects range from mild to very serious depending on the antibiotics used, the microbial organisms targeted, and the individual patient. Side effects may reflect the pharmacological or toxicological properties of the antibiotic or may involve hypersensitivity reactions or anaphylaxis. Safety profiles of newer drugs are often not as well established as for those that have a long history of use. Adverse effects range from fever and nausea to major allergic reactions, including photodermatitis and anaphylaxis. Common side-effects include diarrhea, resulting from disruption of the species composition in the intestinal flora, resulting, for example, in overgrowth of pathogenic bacteria, such as Clostridium difficile. Antibacterials can also affect the vaginal flora, and may lead to overgrowth of yeast species of the genus Candida in the vulvo-vaginal area. Additional side-effects can result from interaction with other drugs, such as elevated risk of tendon damage from administration of a quinolone antibiotic with a systemic corticosteroid. Some scientists have hypothesized that the indiscriminate use of antibiotics alter the host microbiota and this has been associated with chronic disease.
What negative effects can antibiotics have on the vaginal area?
A: yeast

Context and question: Although Calvin and Huldrych Zwingli honored Mary as the Mother of God in the 16th century, they did so less than Martin Luther. Thus the idea of respect and high honor for Mary was not rejected by the first Protestants; but, they came to criticize the Roman Catholics for venerating Mary. Following the Council of Trent in the 16th century, as Marian veneration became associated with Catholics, Protestant interest in Mary decreased. During the Age of the Enlightenment any residual interest in Mary within Protestant churches almost disappeared, although Anglicans and Lutherans continued to honor her.
Which Protestant churches began honoring Mary before the 16th century?
Answer: unanswerable

Question: If access is gained to a car's internal controller area network, it is possible to disable the brakes and turn the steering wheel. Computerized engine timing, cruise control, anti-lock brakes, seat belt tensioners, door locks, airbags and advanced driver assistance systems make these disruptions possible, and self-driving cars go even further. Connected cars may use wifi and bluetooth to communicate with onboard consumer devices, and the cell phone network to contact concierge and emergency assistance services or get navigational or entertainment information; each of these networks is a potential entry point for malware or an attacker. Researchers in 2011 were even able to use a malicious compact disc in a car's stereo system as a successful attack vector, and cars with built-in voice recognition or remote assistance features have onboard microphones which could be used for eavesdropping.
Is there an answer to this question: When were self-driving cars built?

Answer: unanswerable

Problem: Modern history:

A series of international crises strained the League to its limits, the earliest being the invasion of Manchuria by Japan and the Abyssinian crisis of 1935/36 in which Italy invaded Abyssinia, one of the only free African nations at that time. The League tried to enforce economic sanctions upon Italy, but to no avail. The incident highlighted French and British weakness, exemplified by their reluctance to alienate Italy and lose her as their ally. The limited actions taken by the Western powers pushed Mussolini's Italy towards alliance with Hitler's Germany anyway. The Abyssinian war showed Hitler how weak the League was and encouraged the remilitarization of the Rhineland in flagrant disregard of the Treaty of Versailles. This was the first in a series of provocative acts culminating in the invasion of Poland in September 1939 and the beginning of the Second World War.

Who was first to invade Manchuria?
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A:
Japan