Problem: The two largest metropolitan areas have subway systems: Lisbon Metro and Metro Sul do Tejo in the Lisbon Metropolitan Area and Porto Metro in the Porto Metropolitan Area, each with more than 35 km (22 mi) of lines. In Portugal, Lisbon tram services have been supplied by the Companhia de Carris de Ferro de Lisboa (Carris), for over a century. In Porto, a tram network, of which only a tourist line on the shores of the Douro remain, began construction on 12 September 1895 (a first for the Iberian Peninsula). All major cities and towns have their own local urban transport network, as well as taxi services.
How long are each of the subway systems?
The answer is the following: more than 35 km (22 mi)

Problem: The foundation of Northwestern University is traceable to a meeting on May 31, 1850 of nine prominent Chicago businessmen, Methodist leaders and attorneys who had formed the idea of establishing a university to serve what had once been known as the Northwest Territory. On January 28, 1851, the Illinois General Assembly granted a charter to the Trustees of the North-Western University, making it the first chartered university in Illinois. The school's nine founders, all of whom were Methodists (three of them ministers), knelt in prayer and worship before launching their first organizational meeting. Although they affiliated the university with the Methodist Episcopal Church, they were committed to non-sectarian admissions, believing that Northwestern should serve all people in the newly developing territory.
In what environment was the foundation for Northwestern University planned on May 31, 1850?
The answer is the following: a meeting

Problem: The first lighting used on an airport was during the latter part of the 1920s; in the 1930s approach lighting came into use. These indicated the proper direction and angle of descent. The colours and flash intervals of these lights became standardized under the International Civil Aviation Organization (ICAO). In the 1940s, the slope-line approach system was introduced. This consisted of two rows of lights that formed a funnel indicating an aircraft's position on the glideslope. Additional lights indicated incorrect altitude and direction.
When did approach lighting come into use?
The answer is the following: 1930s

Problem: Helping his father in Visible Speech demonstrations and lectures brought Bell to Susanna E. Hull's private school for the deaf in South Kensington, London. His first two pupils were "deaf mute" girls who made remarkable progress under his tutelage. While his older brother seemed to achieve success on many fronts including opening his own elocution school, applying for a patent on an invention, and starting a family, Bell continued as a teacher. However, in May 1870, Melville died from complications due to tuberculosis, causing a family crisis. His father had also suffered a debilitating illness earlier in life and had been restored to health by a convalescence in Newfoundland. Bell's parents embarked upon a long-planned move when they realized that their remaining son was also sickly. Acting decisively, Alexander Melville Bell asked Bell to arrange for the sale of all the family property,[N 8] conclude all of his brother's affairs (Bell took over his last student, curing a pronounced lisp), and join his father and mother in setting out for the "New World". Reluctantly, Bell also had to conclude a relationship with Marie Eccleston, who, as he had surmised, was not prepared to leave England with him.
What sort of student attended Susanna E. Hull?
The answer is the following:
deaf