General relativity includes a dynamical spacetime, so it is difficult to see how to identify the conserved energy and momentum. Noether's theorem allows these quantities to be determined from a Lagrangian with translation invariance, but general covariance makes translation invariance into something of a gauge symmetry. The energy and momentum derived within general relativity by Noether's presecriptions do not make a real tensor for this reason. Einstein argued that this is true for fundamental reasons, because the gravitational field could be made to vanish by a choice of coordinates. He maintained that the non-covariant energy momentum pseudotensor was in fact the best description of the energy momentum distribution in a gravitational field. This approach has been echoed by Lev Landau and Evgeny Lifshitz, and others, and has become standard. The use of non-covariant objects like pseudotensors was heavily criticized in 1917 by Erwin Schrodinger and others.
What question would one ask from this paragraph?
Answer: When did the standard approach to energy momentum become criticized?

The inhabited history of the Las Vegas Valley stretches to 23,000 b.c. , when much of the area was covered by a prehistoric lake. During this period, the indigenous people lived in caves, hunting the mammals that gathered at the shoreline. The landscape of the valley changed dramatically over the next 200 centuries. The glaciers feeding the lake melted away and the lake evaporated. Fossils tell an obscure story of man's slow and sporadic development. Around 3000 b.c. , native Archaic Indians began to develop a lasting hunting and gathering culture. By this time, the valley was in much the same geographic state as it exists in today, with one exceptionthe presence of artesian springs that bubbled to the surface in several areas. These springs fed a network of streams draining through the Las Vegas Wash to the Colorado River. The areas surrounding the springs were desert oases: sprawling collections of grasses, trees, and wildlife. Many springs lay in areas that would eventually become the center of the modern Las Vegas metropolis. For about 4000 years, the Archaics thrived in a culture that included many signs of early civilization. Signs of even more advancement appeared halfway through the first millennium a.d. , when the Anasazi Indians inhabited the valley. Far more progressive than the Archaics, the Anasazi utilized such formal agricultural techniques as irrigation to assist their harvest. This permitted the Anasazi to achieve a benchmark of advanced societythe ability to live in permanent shelters year-round without need to follow wildlife. Mysteriously, the Anasazi vanished from the valley around a.d.
What question would one ask from this paragraph?
Answer: When did the artesian springs first appear?

Peter was a very sad puppy. He had been inside of the pet store for a very long time. In fact, he had been there for three months! Peter had seen many other puppies find a person; he began to wonder why he could not get one. He thought that maybe his fur was not pretty enough or maybe his bark was not loud enough. He tried and tried to please every person who came to the store, but they all picked smaller puppies. However, one day all of this changed. Sammie came into the store looking for a golden puppy. She wanted a puppy she could snuggle with. It so happened that Peter was very sad and tired that day. Sammie came to hold him. Peter wanted to show off his bark, but he was too tired. He fell right to sleep. Sammie loved him at once and loved holding him in her arms. Sammie took Peter home that day, and they made lots of fun memories.
What question would one ask from this paragraph?
Answer: Why was Peter sad?

At 9:48, a representative from the White House shelter asked if there were any indications of another hijacked aircraft. The deputy director for operations mentioned the Delta flight and concluded that "that would be the fourth possible hijack." At 9:49, the commander of NORAD directed all air sovereignty aircraft to battle stations, fully armed. At 9:59, an Air Force lieutenant colonel working in the White House Military Office joined the conference and stated he had just talked to Deputy National Security Advisor Stephen Hadley. The White House requested (1) the implementation of continuity of government measures, (2) fighter escorts for Air Force One, and (3) a fighter combat air patrol over Washington, D.C. By 10:03, when United 93 crashed in Pennsylvania, there had been no mention of its hijacking and the FAA had not yet been added to the teleconference. The President and the Vice President The President was seated in a classroom when, at 9:05, Andrew Card whispered to him: "A second plane hit the second tower. America is under attack." The President told us his instinct was to project calm, not to have the country see an excited reaction at a moment of crisis. The press was standing behind the children; he saw their phones and pagers start to ring. The President felt he should project strength and calm until he could better understand what was happening. The President remained in the classroom for another five to seven minutes, while the children continued reading. He then returned to a holding room shortly before 9:15, where he was briefed by staff and saw television coverage. He next spoke to Vice President Cheney, Dr. Rice, New York Governor George Pataki, and FBI Director Robert Mueller. He decided to make a brief statement from the school before leaving for the airport. The Secret Service told us they were anxious to move the President to a safer location, but did not think it imperative for him to run out the door. Between 9:15 and 9:30, the staff was busy arranging a return to Washington, while the President consulted his senior advisers about his remarks. No one in the traveling party had any information during this time that other aircraft were hijacked or missing. Staff was in contact with the White House Situation Room, but as far as we could determine, no one with the President was in contact with the Pentagon.
What question would one ask from this paragraph?
Answer:
Who went to a holding room shortly before 9:15