If 'ski rps tri' stands for 'nice Sunday morning'; 'teh sti rps' stands for 'every Tuesday morning' and 'ski ptr qlm' stands for 'nice market place',
what would 'Sunday' stands for ?
In the first and second statements, the common code word is 'rps' and the common word is 'morning'.
So, 'rps' means 'morning'
In the first and third statements, common code is 'ski' and the common word is 'nice'.
So, 'ski' means 'nice'.