instruction:
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.
question:
Passage: Another potential weapon system for anti-aircraft use is the laser. Although air planners have imagined lasers in combat since the late 1960s, only the most modern laser systems are currently reaching what could be considered "experimental usefulness". In particular the Tactical High Energy Laser can be used in the anti-aircraft and anti-missile role. If current developments continue, some[who?] believe it is reasonable to suggest that lasers will play a major role in air defence starting in the next ten years. Question: When do some people believe that lasers can play a more prominent role in air defence?
answer:
in the next ten years


question:
Passage: During the 1800s Christian missionaries from Great Britain and the United States followed traders to the Hawaiian islands. Long-termly, the Anglo-Saxon presence negatively impacted the level of regard Hawaiian royal women held for their own indigenous looks. For centuries prior the arrival of Christians, first nation Hawaiian aesthetics, such as dark skin and ample bodies, had been considered signs of nobility. No matter how much they adapted their mannerisms to Western standard, some of the Anglo-Saxon missionaries were relentless in referring to the indigenous women as "Hawaiian squaws." By the last half of the 19th century, some Hawaiian women began marrying European men who found them exotic. The men, however, selected Hawaiian women who were thinner and paler in complexion. Question: When would white men marry the paler and thinner Hawaiian ladies?
answer:
By the last half of the 19th century


question:
Passage: Von Neumann introduced the study of rings of operators, through the von Neumann algebras. A von Neumann algebra is a *-algebra of bounded operators on a Hilbert space that is closed in the weak operator topology and contains the identity operator. The von Neumann bicommutant theorem shows that the analytic definition is equivalent to a purely algebraic definition as an algebra of symmetries. The direct integral was introduced in 1949 by John von Neumann. One of von Neumann's analyses was to reduce the classification of von Neumann algebras on separable Hilbert spaces to the classification of factors. Question: When was direct integral introduced by von Neumann?
answer:

1949