In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Q: What needs consistency?, Context: The simplest valve gears give events of fixed length during the engine cycle and often make the engine rotate in only one direction. Most however have a reversing mechanism which additionally can provide means for saving steam as speed and momentum are gained by gradually "shortening the cutoff" or rather, shortening the admission event; this in turn proportionately lengthens the expansion period. However, as one and the same valve usually controls both steam flows, a short cutoff at admission adversely affects the exhaust and compression periods which should ideally always be kept fairly constant; if the exhaust event is too brief, the totality of the exhaust steam cannot evacuate the cylinder, choking it and giving excessive compression ("kick back").[citation needed]

A: exhaust and compression periods
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Q: What controlling entity might the low countries been afraid of?, Context: In 1579 a number of the northern provinces of the Low Countries signed the Union of Utrecht, in which they promised to support each other in their defence against the Spanish army. This was followed in 1581 by the Act of Abjuration, the declaration of independence of the provinces from Philip II.

A: provinces from Philip II
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Q: Mistinguett sang at Casino de Paris and which other venue?, Context: The music hall and cabaret are famous Paris institutions. The Moulin Rouge was opened in 1889. It was highly visible because of its large red imitation windmill on its roof, and became the birthplace of the dance known as the French Cancan. It helped make famous the singers Mistinguett and Édith Piaf and the painter Toulouse-Lautrec, who made posters for the venue. In 1911, the dance hall Olympia Paris invented the grand staircase as a settling for its shows, competing with its great rival, the Folies Bergère, Its stars in the 1920s included the American singer and dancer Josephine Baker. The Casino de Paris presented many famous French singers, including Mistinguett, Maurice Chevalier, and Tino Rossi. Other famous Paris music halls include Le Lido, on the Champs-Élysées, opened in 1946; and the Crazy Horse Saloon, featuring strip-tease, dance and magic, opened in 1951. The Olympia Paris has presented Edith Piaf, Marlene Dietrich, Miles Davis, Judy Garland, and the Grateful Dead. A half dozen music halls exist today in Paris, attended mostly visitors to the city.

A:
Moulin Rouge
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