In the question given below, the passage consists of six sentences. The first and sixth sentences are given at the beginning. The middle four sentences have been removed and jumbled up. They are labelled as, P, Q, R, and S. Find out the proper order for the four sentences.
S1: The study of speech disorders due to brain injury suggests that patients can think without having adequate control over their language.
P: But, they succeed in playing games of chess.
Q: Some patients, for example, fail to find the names of objects presented to them.
R: They can even use the concepts needed for chess-playing, though they are unable to express many of the concepts in ordinary language.
S: They even find it difficult to interpret long written notices.
S6: How they manage to do this, we do not know.
The proper sequence should be