TASK DEFINITION: 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.
PROBLEM: Sentence1: a flashlight converts chemical energy into light energy. 
Sentence2: PALight Flashlights are the ultimate personal LED flashlights.

SOLUTION: flashlight

PROBLEM: Sentence1: exercise increases a body 's strength. 
Sentence2: Exercise is more than running and lifting.

SOLUTION: exercise

PROBLEM: Sentence1: Clams are mollusks that live in the sea or in freshwater. 
Sentence2: clams have a circulatory system with one or two hearts that pump blood.

SOLUTION:
Clams