Sentence 1: Throughout Peter's math class, he had a bad headache. 
 Sentence 3: However, he had to leave 45 minutes before the end of class 
 Sentence 4:  His friend decided to look for him 
 Sentence 5:  He found peter, throwing up in the bathroom 
 Option 1: Although it was hard for him to pay attention, he stayed for the whole class. 
 Option 2: Although it was hard for him to pay attention, he tried to be calm.