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: A great part of Arabia is desert. 
P: The sand is so hot that you cannot walk over it with your bare feet in the day time.
Q: These springs are few and far apart, but wherever there is one, green grass very soon covers the ground all around it. 
R: Here there is nothing but sand and rock.
S: Here and there in the desert are springs of water that come from deep down under the ground. 
S6: Such place is called an oasis.