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: erosion causes a river to become deeper and wider. 
Sentence2: On the contrary, the NILE is the longest river in Africa.

SOLUTION: river

PROBLEM: Sentence1: dew is formed when water vapor condenses over night. 
Sentence2: When water vapor condenses overnight, the temperature has reached the dew point.

SOLUTION: condenses

PROBLEM: Sentence1: Mutations that lead to cancer usually occur in genes that control the cell cycle. 
Sentence2: Radiation causes mutation.

SOLUTION:
Mutations