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

Ex Input:
What needs consistency?, Context: The simplest valve gears give events of fixed length during the engine cycle and often make the engine rotate in only one direction. Most however have a reversing mechanism which additionally can provide means for saving steam as speed and momentum are gained by gradually "shortening the cutoff" or rather, shortening the admission event; this in turn proportionately lengthens the expansion period. However, as one and the same valve usually controls both steam flows, a short cutoff at admission adversely affects the exhaust and compression periods which should ideally always be kept fairly constant; if the exhaust event is too brief, the totality of the exhaust steam cannot evacuate the cylinder, choking it and giving excessive compression ("kick back").[citation needed]

Ex Output:
exhaust and compression periods


Ex Input:
How do Presbyterians demonstrate their faith with actions as opposed to words?, Context: Presbyterians place great importance upon education and lifelong learning. Continuous study of the scriptures, theological writings, and understanding and interpretation of church doctrine are embodied in several statements of faith and catechisms formally adopted by various branches of the church, often referred to as "subordinate standards". It is generally considered that the point of such learning is to enable one to put one's faith into practice; some Presbyterians generally exhibit their faith in action as well as words, by generosity, hospitality, as well as proclaiming the gospel of Christ.

Ex Output:
generosity, hospitality


Ex Input:
What did the two languages have in common?, Context: The strength of the Viking influence on Old English appears from the fact that the indispensable elements of the language - pronouns, modals, comparatives, pronominal adverbs (like "hence" and "together"), conjunctions and prepositions - show the most marked Danish influence; the best evidence of Scandinavian influence appears in the extensive word borrowings for, as Jespersen indicates, no texts exist in either Scandinavia or in Northern England from this time to give certain evidence of an influence on syntax. The change to Old English from Old Norse was substantive, pervasive, and of a democratic character. Old Norse and Old English resembled each other closely like cousins and with some words in common, they roughly understood each other; in time the inflections melted away and the analytic pattern emerged. It is most “important to recognize that in many words the English and Scandinavian language differed chiefly in their inflectional elements. The body of the word was so nearly the same in the two languages that only the endings would put obstacles in the way of mutual understanding. In the mixed population which existed in the Danelaw these endings must have led to much confusion, tending gradually to become obscured and finally lost.” This blending of peoples and languages happily resulted in “simplifying English grammar.”

Ex Output:
some words