Task: Coherence Classification
Input (English): Sentence 1: Viktor could not get his microscope to focus. 
 Sentence 3: His professor also could not get it to focus 
 Sentence 4:  The professor wiped the lens with a solvent 
 Sentence 5:  He was then able to focus the lens 
 Given Sentence 2: His professor came to help.
Output (English): Yes