Question: As computers grew in speed and capability, a number of general-purpose database systems emerged; by the mid-1960s a number of such systems had come into commercial use. Interest in a standard began to grow, and Charles Bachman, author of one such product, the Integrated Data Store (IDS), founded the "Database Task Group" within CODASYL, the group responsible for the creation and standardization of COBOL. In 1971 the Database Task Group delivered their standard, which generally became known as the "CODASYL approach", and soon a number of commercial products based on this approach entered the market.
Is there an answer to this question: When were DBMSs last used commercially?

Answer: unanswerable


Question: The M. tuberculosis complex (MTBC) includes four other TB-causing mycobacteria: M. bovis, M. africanum, M. canetti, and M. microti. M. africanum is not widespread, but it is a significant cause of tuberculosis in parts of Africa. M. bovis was once a common cause of tuberculosis, but the introduction of pasteurized milk has almost completely eliminated this as a public health problem in developed countries. M. canetti is rare and seems to be limited to the Horn of Africa, although a few cases have been seen in African emigrants. M. microti is also rare and is seen almost only in immunodeficient people, although its prevalence may be significantly underestimated.
Is there an answer to this question: Which bacterium has likely been overestimated?

Answer: unanswerable


Question: Zhejiang is the home of Yueju (越劇), one of the most prominent forms of Chinese opera. Yueju originated in Shengzhou and is traditionally performed by actresses only, in both male and female roles. Other important opera traditions include Yongju (of Ningbo), Shaoju (of Shaoxing), Ouju (of Wenzhou), Wuju (of Jinhua), Taizhou Luantan (of Taizhou) and Zhuji Luantan (of Zhuji).
Is there an answer to this question:  What is one of the least prominent forms of Chinese opera?

Answer: unanswerable


Question: San Diego and its backcountry are subject to periodic wildfires. In October 2003, San Diego was the site of the Cedar Fire, which has been called the largest wildfire in California over the past century. The fire burned 280,000 acres (1,100 km2), killed 15 people, and destroyed more than 2,200 homes. In addition to damage caused by the fire, smoke resulted in a significant increase in emergency room visits due to asthma, respiratory problems, eye irritation, and smoke inhalation; the poor air quality caused San Diego County schools to close for a week. Wildfires four years later destroyed some areas, particularly within the communities of Rancho Bernardo, Rancho Santa Fe, and Ramona.
Is there an answer to this question: How many years after the Cedar Fire did additional fires destroy Rancho Santa Fe?

Answer:
four years later