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.
Input: Sentence1: Viruses are so small that they can be seen only with an electron microscope. 
Sentence2: Once the camera is tuned with the microscope, the focusing depends on the microscope lens.

microscope