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: An accounting period is simply a period of time. 
Sentence2: seconds are used to measure a period.

SOLUTION: period

PROBLEM: Sentence1: if humans disturb animals in a location then those animals will move to a different location. 
Sentence2: The human being is self-aware.

SOLUTION: humans

PROBLEM: Sentence1: Migrants typically travel long distances. 
Sentence2: Migrant birds arrive.

SOLUTION:
Migrants