Problem: Unmarked vehicles are used primarily for sting operations or apprehending criminals without alerting them to their presence. Some police forces use unmarked or minimally marked cars for traffic law enforcement, since drivers slow down at the sight of marked police vehicles and unmarked vehicles make it easier for officers to catch speeders and traffic violators. This practice is controversial, with for example, New York State banning this practice in 1996 on the grounds that it endangered motorists who might be pulled over by people impersonating police officers.
When do police often use marked cars?
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Answer: unanswerable

Problem: The rulers of the expansionist Qin dynasty, based in present-day Gansu and Shaanxi, were only the first strategists to realize that the area's military importance matched its commercial and agricultural significance. The Sichuan basin is surrounded by the Himalayas to the west, the Qin Mountains to the north, and mountainous areas of Yunnan to the south. Since the Yangtze flows through the basin and then through the perilous Yangzi Gorges to eastern and southern China, Sichuan was a staging area for amphibious military forces and a refuge for political refugees.[citation needed]
Where was the Qin dynasty based?
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Answer: present-day Gansu and Shaanxi

Problem: In mid-2015 the government of Zhejiang recognised folk religion as "civil religion" beginning the registration of more than twenty thousand folk religious associations. Buddhism has an important presence since its arrival in Zhejiang 1,800 years ago.
When did Buddhism leave Zhejiang?
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Answer:
unanswerable