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The Wagner tuba, a modified member of the horn family, appears in Richard Wagner's cycle Der Ring des Nibelungen and several other works by Strauss, Bela Bartok, and others; it has a prominent role in Anton Bruckner's Symphony No. 7 in E Major. Cornets appear in Pyotr Ilyich Tchaikovsky's ballet Swan Lake, Claude Debussy's La Mer, and several orchestral works by Hector Berlioz. Unless these instruments are played by members doubling on another instrument (for example, a trombone player changing to euphonium for a certain passage), orchestras will use freelance musicians to augment their regular rosters.
Who wrote the ballet Swan Lake?
A: Pyotr Ilyich Tchaikovsky

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Due to the patriarchal nature of Arab society, Arab men, including during the slave trade in North Africa, enslaved more black women than men. They used more black female slaves in domestic service and agriculture than males. The men interpreted the Qur'an to permit sexual relations between a male master and his female slave outside of marriage (see Ma malakat aymanukum and sex), leading to many mixed-race children. When an enslaved woman became pregnant with her Arab master's child, she was considered as umm walad or "mother of a child", a status that granted her privileged rights. The child was given rights of inheritance to the father's property, so mixed-race children could share in any wealth of the father. Because the society was patrilineal, the children took their fathers' social status at birth and were born free.
Who was enslaved more often?
A: black women

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The 132nd Street Community Garden is located on 132nd Street between Adam Clayton Powell Jr. Boulevard and Malcolm X Boulevard. In 1997, the lot received a garden makeover; the Borough President's office funded the installation of a $100,000 water distribution system that keeps the wide variety of trees green. The garden also holds a goldfish pond and several benches. The spirit of the neighborhood lives in gardens like this one, planted and tended by local residents.
Who funded the 132nd Street Community Garden's water distribution system?
A: Borough President's office

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The BeiDou Navigation Satellite System (BDS, simplified Chinese: ; traditional Chinese: ; pinyin: Beidou weixing daohang xitong) is a Chinese satellite navigation system. It consists of two separate satellite constellations a limited test system that has been operating since 2000, and a full-scale global navigation system that is currently under construction.
Which system is no longer under construction?
A:
unanswerable