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.

Input: Consider Input: Sentence1: a pulley is used for lifting objects.
Sentence2: Resistance exercises are weight-lifting exercises.

Output: lifting

Input: Consider Input: Sentence1: friction causes the temperature of an object to increase.
Sentence2: When we increase the temperature of objects, they always expand.

Output: increase

Input: Consider Input: Sentence1: safety goggles are used for protecting the eyes during experiments.
Sentence2: Firm plastic eyeglasses or goggles are better.
Output: goggles