COLOMBO, July 24 (Reuters) - Scoreboard at close on the first day of the second test between Sri Lanka and South Africa on Thursday. Sri Lanka won the toss Sri Lanka first innings U Tharanga c De Kock b Steyn 11 K Silva c de Villiers b Duminy 44 K Sangakkara c Tahir b Steyn 0 M Jayawardene not out 140 A Mathews c De Kock b Duminy 63 K Vithanage c De Villiers b Morkel 13 N Dickwella not out 12 Extras: (b-10,