In this task, you are given two sentences in the English language (Sentence 1 and Sentence 2). Your task is to identify the connecting word between the two sentences.
--------
Question: Sentence 1:Most of PCPD pump failures are due to this elastomer part . Sentence 2:However , the operating conditions and environment should not degrade or induce mechanical failure of the elastomer part for the life of the equipment .

Answer: however


Question: Sentence 1:So you learn to pay attention to personal relationships . Sentence 2:But that does n't mean you lie to people .

Answer: but


Question: Sentence 1:Anand , the tournament 's hitherto - untroubled No. 1 seed , breezed through the quarterfinal round against his longtime rival Vassily Ivanchuk . Sentence 2:But Boris Gelfand gave Anand a challenge in the semi-final , and the match was not settled until a sudden - death blitz game .

Answer:
but