Instructions: 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.
Input: Sentence 1:The second pre-production train was also tested on the Victoria line during engineering hours , and was expected to begin trial running in full passenger service in July 2008 . Sentence 2:However , this date slipped twice , first to January 2009 and then to July 2009 .
Output:
however