Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.
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Question: Sentence1: an earthquake causes the ground to shake. 
Sentence2: A number of buildings in Istanbul also were damaged in the earthquake.

Answer: earthquake


Question: Sentence1: Faster metabolism means more calories consumed, and usually, weight loss. 
Sentence2: mammals generate heat by consuming calories.

Answer: calories


Question: Sentence1: a pulley is used for lifting objects. 
Sentence2: a crane uses pulleys.

Answer:
pulley