TASK DEFINITION: This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
PROBLEM: Passage: The Treaty of Paris stood until 1871, when France was defeated by Prussia in the Franco-Prussian War of 1870–1871. While Prussia and several other German states united to form a powerful German Empire, the Emperor of the French, Napoleon III, was deposed to permit the formation of a Third French Republic. During his reign, Napoleon III, eager for the support of the United Kingdom, had opposed Russia over the Eastern Question. Russian interference in the Ottoman Empire, however, did not in any significant manner threaten the interests of France. Thus, France abandoned its opposition to Russia after the establishment of a republic. Encouraged by the decision of the French, and supported by the German minister Otto von Bismarck, Russia renounced the Black Sea clauses of the treaty agreed to in 1856. As the United Kingdom alone could not enforce the clauses, Russia once again established a fleet in the Black Sea. Question: Between what years did the  Franco-Prussian War take place?

SOLUTION: 1870–1871

PROBLEM: Passage: A elevator of this kind uses a vacuum on top of the cab and a valve on the top of the "shaft" to move the cab upwards and closes the valve in order to keep the cab at the same level. a diaphragm or a piston is used as a "brake" if there's a sudden increase in pressure avove the cab. however, to go down, it opens the valve so that the air can pressurize the top of the "shaft", allowing the cab to go down by its own weight. this also means that in case of a power failure, the cab will automatically go down. the "shaft" is made of acrilic, is always round, due to the shape of the vacuum pump turbine. in order to keep the air inside of the cab, rubber seals are used. due to technical limitations, these elevators have a low capacity. they usually allow 1-3 passengers and up to 525 lbs. Question: For sudden surges in pressure above the cab, what is used as a "brake"?

SOLUTION: a diaphragm or a piston

PROBLEM: Passage: According to Sun Jiadong, the chief designer of the navigation system, "Many organizations have been using our system for a while, and they like it very much." Question: What did Sun Jiadong have to say about the BeiDou navigation system?

SOLUTION:
"Many organizations have been using our system for a while, and they like it very much."