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: a thermometer is used to measure temperature. 
Sentence2: a thermometer is used to measure heat.

Answer: a


Question: Sentence1: a seismometer is used to measure the strength or magnitude of an earthquake. 
Sentence2: Seismometer Calibration : Instructions on how to calibrate a homemade seismometer.

Answer: seismometer


Question: Sentence1: Bacteria may spread directly from one person to another. 
Sentence2: microbial control agents may spread directly from one person to another.

Answer:
another