In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

[EX Q]: What would an engine driver have to do to adjust the more modern type of valve?, Context: Steam engines frequently possess two independent mechanisms for ensuring that the pressure in the boiler does not go too high; one may be adjusted by the user, the second is typically designed as an ultimate fail-safe. Such safety valves traditionally used a simple lever to restrain a plug valve in the top of a boiler. One end of the lever carried a weight or spring that restrained the valve against steam pressure. Early valves could be adjusted by engine drivers, leading to many accidents when a driver fastened the valve down to allow greater steam pressure and more power from the engine. The more recent type of safety valve uses an adjustable spring-loaded valve, which is locked such that operators may not tamper with its adjustment unless a seal illegally is broken. This arrangement is considerably safer.[citation needed]
[EX A]: seal illegally is broken

[EX Q]: Who has studied the Mahayana?, Context: There is no evidence that Mahāyāna ever referred to a separate formal school or sect of Buddhism, but rather that it existed as a certain set of ideals, and later doctrines, for bodhisattvas. Initially it was known as Bodhisattvayāna (the "Vehicle of the Bodhisattvas"). Paul Williams has also noted that the Mahāyāna never had nor ever attempted to have a separate Vinaya or ordination lineage from the early schools of Buddhism, and therefore each bhikṣu or bhikṣuṇī adhering to the Mahāyāna formally belonged to an early school. This continues today with the Dharmaguptaka ordination lineage in East Asia, and the Mūlasarvāstivāda ordination lineage in Tibetan Buddhism. Therefore Mahāyāna was never a separate rival sect of the early schools. From Chinese monks visiting India, we now know that both Mahāyāna and non-Mahāyāna monks in India often lived in the same monasteries side by side.
[EX A]: Paul Williams

[EX Q]: What can you find in a library?, Context: Nanjing Library, founded in 1907, houses more than 10 million volumes of printed materials and is the third largest library in China, after the National Library in Beijing and Shanghai Library. Other libraries, such as city-owned Jinling Library and various district libraries, also provide considerable amount of information to citizens. Nanjing University Library is the second largest university libraries in China after Peking University Library, and the fifth largest nationwide, especially in the number of precious collections.
[EX A]:
printed materials