7 of 8 add language tag

C: 115

c,l;main(n,i){for(scanf("%d",&n),i=3,l=2;n;l=c==i?n-=i==l+2,i:l,i++)for(c=2;c<i&&i%c++;);printf("%d, %d\n",l-2,l);}

Sample run:

$ for i in $(seq 1 10); do echo $i | ./twinprimes; done
3, 5
5, 7
11, 13
17, 19
29, 31
41, 43
59, 61
71, 73
101, 103
107, 109