Problem: Peace between England and the Netherlands in 1688 meant that the two countries entered the Nine Years' War as allies, but the conflict—waged in Europe and overseas between France, Spain and the Anglo-Dutch alliance—left the English a stronger colonial power than the Dutch, who were forced to devote a larger proportion of their military budget on the costly land war in Europe. The 18th century saw England (after 1707, Britain) rise to be the world's dominant colonial power, and France becoming its main rival on the imperial stage.
When did England and the Netherlands make peace?
The answer is the following: 1688

Problem: Due to the patriarchal nature of Arab society, Arab men, including during the slave trade in North Africa, enslaved more black women than men. They used more black female slaves in domestic service and agriculture than males. The men interpreted the Qur'an to permit sexual relations between a male master and his female slave outside of marriage (see Ma malakat aymanukum and sex), leading to many mixed-race children. When an enslaved woman became pregnant with her Arab master's child, she was considered as umm walad or "mother of a child", a status that granted her privileged rights. The child was given rights of inheritance to the father's property, so mixed-race children could share in any wealth of the father. Because the society was patrilineal, the children took their fathers' social status at birth and were born free.
What does umm walad mean?
The answer is the following: "mother of a child"

Problem: Public demand caused the government in October 1940 to build new deep shelters:189–190 within the Underground to hold 80,000 people but were not completed until the period of heaviest bombing had passed. By the end of 1940 significant improvements had been made in the Underground and in many other large shelters. Authorities provided stoves and bathrooms and canteen trains provided food. Tickets were issued for bunks in large shelters to reduce the amount of time spent queuing. Committees quickly formed within shelters as informal governments, and organisations such as the British Red Cross and the Salvation Army worked to improve conditions. Entertainment included concerts, films, plays and books from local libraries. 
What year did the government start to build new deep shelters?
The answer is the following: 1940

Problem: The modern concept of an abstract group developed out of several fields of mathematics. The original motivation for group theory was the quest for solutions of polynomial equations of degree higher than 4. The 19th-century French mathematician Évariste Galois, extending prior work of Paolo Ruffini and Joseph-Louis Lagrange, gave a criterion for the solvability of a particular polynomial equation in terms of the symmetry group of its roots (solutions). The elements of such a Galois group correspond to certain permutations of the roots. At first, Galois' ideas were rejected by his contemporaries, and published only posthumously. More general permutation groups were investigated in particular by Augustin Louis Cauchy. Arthur Cayley's On the theory of groups, as depending on the symbolic equation θn = 1 (1854) gives the first abstract definition of a finite group.
 Who developed a theory giving the first abstract definition of a finite group?
The answer is the following:
Arthur Cayley