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.

Sentence1: Telephone Telephone calls are expensive. 
Sentence2: Communicating by transmitting sound is expensive.
expensive

Sentence1: Asbestos is a dangerous carcinogen. 
Sentence2: Asbestos causes cancer.
Asbestos

Sentence1: an earthquake causes the ground to shake. 
Sentence2: Fault movement causes the ground to shake.

ground