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: Returning to the basic concept of current flows in a conductor, consider what happens if a half-wave dipole is not connected to a feed point, but instead shorted out. Electrically this forms a single 12-wavelength element. But the overall current pattern is the same; the current will be zero at the two ends, and reach a maximum in the center. Thus signals near the design frequency will continue to create a standing wave pattern. Any varying electrical current, like the standing wave in the element, will radiate a signal. In this case, aside from resistive losses in the element, the rebroadcast signal will be significantly similar to the original signal in both magnitude and shape. If this element is placed so its signal reaches the main dipole in-phase, it will reinforce the original signal, and increase the current in the dipole. Elements used in this way are known as passive elements. Question: What is a half wave dipole need to be coupled with in most instances?
answer:
feed point

question:
Passage: The tradition holds that Virgil was born in the village of Andes, near Mantua in Cisalpine Gaul. Analysis of his name has led to beliefs that he descended from earlier Roman colonists. Modern speculation ultimately is not supported by narrative evidence either from his own writings or his later biographers. Macrobius says that Virgil's father was of a humble background; however, scholars generally believe that Virgil was from an equestrian landowning family which could afford to give him an education. He attended schools in Cremona, Mediolanum, Rome and Naples. After considering briefly a career in rhetoric and law, the young Virgil turned his talents to poetry. Question: In which cities did Virgil attend schools?
answer:
Cremona, Mediolanum, Rome and Naples

question:
Passage: There are two major sports centers in Nanjing, Wutaishan Sports Center and Nanjing Olympic Sports Center. Both of these two are comprehensive sports centers, including stadium, gymnasium, natatorium, tennis court, etc. Wutaishan Sports Center was established in 1952 and it was one of the oldest and most advanced stadiums in early time of People's Republic of China. Question: Both Wutaishan Sports Center and Nanjing Olympic Sports Center contain a stadium, gymnasium, natatorium, and what other facility?
answer:
tennis court