In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Input: Consider Input: Passage: The St. Johns River (Spanish: Rio San Juan) is the longest river in the U.S. state of Florida and its most significant one for commercial and recreational use. At 310 miles (500 km) long, it flows north and winds through or borders twelve counties. The drop in elevation from headwaters to mouth is less than 30 feet (9 m); like most Florida waterways, the St. Johns has a very low flow rate 0.3 mph (0.13 m/s) and is often described as "lazy". Numerous lakes are formed by the river or flow into it, but as a river its widest point is nearly 3 miles (5 km) across. The narrowest point is in the headwaters, an unnavigable marsh in Indian River County. The St. Johns drainage basin of 8,840 square miles (22,900 km2) includes some of Florida's major wetlands. It is separated into three major basins and two associated watersheds for Lake George and the Ocklawaha River, all managed by the St. Johns River Water Management District.
A variety of people have lived on or near the St. Johns, including Paleo-indians, Archaic people, Timucua, Mocama, French and Spanish settlers, Seminoles, slaves and freemen, Florida crackers, land developers, tourists and retirees. It has been the subject of William Bartram's journals, Marjorie Kinnan Rawlings' books, and Harriet Beecher Stowe's letters home. Although Florida was the location of the first permanent European settlement in what would become the United States, it was the last U.S. territory on the east coast to be developed; it remained an undeveloped frontier into the 20th century. When attention was turned to the state, however, much of the land was rapidly overdeveloped in a national zeal for progress. The St. Johns, like many Florida rivers, was altered to make way for agricultural and residential centers. It suffered severe pollution and human interference that has diminished the natural order of life in and around the river. In all, 3.5 million people live within the various watersheds that feed into the St. Johns River. The St. Johns, named one of 14 American Heritage Rivers in 1998, was number 6 on a list of America's Ten Most Endangered Rivers in 2008. Restoration efforts are under way for the basins around the St. Johns as Florida continues to deal with population increases in the river's vicinity.

Output: What state remained an undeveloped frontier into the 20th century?

Input: Consider Input: Passage: A boy obsessed with football finds his life changing dramatically once he adds a little Samba. Danny plays on the football team at the all-boys Catholic school he attends in Belfast. Danny's three best friends, who also play on the team, all have different ambitions for their lives. Mickey wants to be a fashion designer so he can get rich and date supermodels. Gary wants to become a magician so he can get rich and meet beautiful women (and presumably saw them in half). And Spike likes to beat people up, so he wants to become a mercenary and do it for a living. But Danny dreams of making football his life.
The players Danny most admires are South Americans, such as Pele and Carlos Riga, who he feels have a special rhythm and flexibility. Wanting to add some of these qualities to his own game, Danny has an idea: he'll take Samba lessons, in the hope that dancing like a South American will help him play like a South American. To the surprise of himself and his friends, Danny turns out to be a pretty good Latin dancer and finds himself smitten with a student in his dance class, Lucy. However, Lucy happens to have a boyfriend, who is a fierce competitor on one of Danny's rival teams. The film also stars Brian Flanagan who plays an inspiring cameo role along with members of Celbridge Town Football Club.

Output: Who are Danny's three best friends?

Input: Consider Input: Passage: Bulgaria occupies a portion of the eastern Balkan peninsula, bordering five countriesGreece and Turkey to the south, Macedonia and Serbia to the west, and Romania to the north. The land borders have a total length of 1,808 kilometres (1,123 mi), and the coastline has a length of 354 kilometres (220 mi). Its total area of 110,994 square kilometres (42,855 sq mi) ranks it as the world's 105th-largest country. Bulgaria's geographic coordinates are 43 N 25 E. The most notable topographical features are the Danubian Plain, the Balkan Mountains, the Thracian Plain, and the Rhodope Mountains. The southern edge of the Danubian Plain slopes upward into the foothills of the Balkans, while the Danube defines the border with Romania. The Thracian Plain is roughly triangular, beginning southeast of Sofia and broadening as it reaches the Black Sea coast.
The Balkan mountains run laterally through the middle of the country. The mountainous southwest has two distinct alpine rangesRila and Pirin, which border the lower but more extensive Rhodope Mountains to the east. Musala, at 2,925 metres (9,596 ft), is the highest point in both Bulgaria and the Balkan peninsula, and the Black Sea coast is the country's lowest point. Plains occupy about one third of the territory, while plateaux and hills occupy 41%. Most rivers are short and with low water levels. The longest river located solely in Bulgarian territory, the Iskar, has a length of 368 kilometres (229 mi). Other major rivers include the Struma and the Maritsa in the south.Bulgaria has a changeable climate, which results from being positioned at the meeting point of the Mediterranean and continental air masses combined with the barrier effect of its mountains. Northern Bulgaria averages 1 C (1.8 F) cooler, and registers 200 millimetres (7.9 in) more precipitation, than the regions south of the Balkan mountains. Temperature amplitudes vary significantly in different areas. The lowest recorded temperature is 38.3 C (36.9 F), while the highest is 45.2 C (113.4 F). Precipitation averages about 630 millimetres (24.8 in) per year, and varies from 500 millimetres (19.7 in) in Dobrudja to more than 2,500 millimetres (98.4 in) in the mountains. Continental air masses bring significant amounts of snowfall during winter.
Output: What country do the Balkan mountains run laterally through?