In a certain code, '253' means 'books are old';
'546' means 'man is old' and
'378' means 'buy good books'.
What stands for 'are' in that code ?
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 ?