Context and question: In 1886, Frank Julian Sprague invented the first practical DC motor, a non-sparking motor that maintained relatively constant speed under variable loads. Other Sprague electric inventions about this time greatly improved grid electric distribution (prior work done while employed by Thomas Edison), allowed power from electric motors to be returned to the electric grid, provided for electric distribution to trolleys via overhead wires and the trolley pole, and provided controls systems for electric operations. This allowed Sprague to use electric motors to invent the first electric trolley system in 1887–88 in Richmond VA, the electric elevator and control system in 1892, and the electric subway with independently powered centrally controlled cars, which were first installed in 1892 in Chicago by the South Side Elevated Railway where it became popularly known as the "L". Sprague's motor and related inventions led to an explosion of interest and use in electric motors for industry, while almost simultaneously another great inventor was developing its primary competitor, which would become much more widespread. The development of electric motors of acceptable efficiency was delayed for several decades by failure to recognize the extreme importance of a relatively small air gap between rotor and stator. Efficient designs have a comparatively small air gap. [a] The St. Louis motor, long used in classrooms to illustrate motor principles, is extremely inefficient for the same reason, as well as appearing nothing like a modern motor.
 Who did Sprague not work for early in his career?
Answer: unanswerable
Context and question: In dominant-party systems, opposition parties are allowed, and there may be even a deeply established democratic tradition, but other parties are widely considered to have no real chance of gaining power. Sometimes, political, social and economic circumstances, and public opinion are the reason for others parties' failure. Sometimes, typically in countries with less of an established democratic tradition, it is possible the dominant party will remain in power by using patronage and sometimes by voting fraud. In the latter case, the definition between dominant and one-party system becomes rather blurred. Examples of dominant party systems include the People's Action Party in Singapore, the African National Congress in South Africa, the Cambodian People's Party in Cambodia, the Liberal Democratic Party in Japan, and the National Liberation Front in Algeria. One-party dominant system also existed in Mexico with the Institutional Revolutionary Party until the 1990s, in the southern United States with the Democratic Party from the late 19th century until the 1970s, in Indonesia with the Golkar from the early 1970s until 1998.
How long did the People's Action Party in Singapore last?
Answer: unanswerable
Context and question: Hard rock had been established as a mainstream genre by 1965. From the end of the 1960s, it became common to divide mainstream rock music into soft and hard rock, with both emerging as major radio formats in the US. Soft rock was often derived from folk rock, using acoustic instruments and putting more emphasis on melody and harmonies. Major artists included Barbra Streisand, Carole King, Cat Stevens, James Taylor and Bread.
Along with Barbra Streisand, Carole King, Cat Stevens and Bread, who was a prominent soft rock artist of this era?
Answer:
James Taylor