Directions: 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 (P, Q, R, S) have been jumbled. Find the proper sequence.

S1: Newton was perhaps the greatest scientist that ever lived.

S6: Newton went home and worked quietly by himself for about 18 months.

P: But when he was only 22, a terrible plague epidemic swept over England.

Q: He was the son of a Lincolnshire farmer, and was born in 1642.

R: Therefore the universities were closed.

S: He went to Cambridge to study mathematics when he was 19.