In the following question the 1st and the last part of the sentence/passage are numbered 1 and 6. The rest of the sentence/ passage is split into four parts and named P, Q, R and S. These four parts are not given in their proper order. Read the sentence/passage and find out which of the four combinations is correct.

1. The manual typewriter is worked by hand.
P. The required letter is thus printed on the paper.
Q. When one of the keys is tapped, a hammer goes and strikes the ribbon against the blank paper.
R. Then the roller automatically moves on, another key is tapped and the next letter is printed.
S. A sheet of paper is clipped against the roller.
6. A person who knows typing, can really work fast on this machine.