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.

[EX Q]: Sentence1: First, the bottle is calibrated with a graduated cylinder. 
Sentence2: calibration is performed with a cylinder.
[EX A]: calibrated

[EX Q]: Sentence1: a flashlight converts chemical energy into light energy. 
Sentence2: Chemical energy converted to light energy requires batteries.
[EX A]: chemical

[EX Q]: Sentence1: Lung cancer is most often caused by exposure to tobacco smoke. 
Sentence2: Enphysema is often caused by exposure to tobacco smoke.
[EX A]:
caused