instruction:
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.
question:
Sentence1: Ice is frozen water. 
Sentence2: ice expands.
answer:
Ice


question:
Sentence1: zinc has a positive impact on the healing of wounds. 
Sentence2: oysters have a positive impact on the healing of wounds.
answer:
has


question:
Sentence1: gases from burning coal and oil dissolving in water in the atmosphere causes acid rain. 
Sentence2: vapors from burning coal and oil dissolving in water in the atmosphere causes acid rain.
answer:

acid