In the following items, each passage consists of six sentences. The first sentence (S1) and the final sentence (S6) are given. The middle four sentences in each have been removed and jumbled up. These are labelled P, Q, R and S. You are required to find out the proper sequence of the four sentences and mark accordingly on the Answer Sheet. 

S1: I passed all the other courses that I took at my university
P: I never once saw a cell through a microscope. 
Q:  This was because all botany students had to spend several hours a week looking through microscopes at plant cells. 
​R: But I could never pass botany. 
S: I could never see through a m1croscope. 
S6: This used to enrage my instructor.