england are 373 for six at stumps on day three , 74 runs ahead of the west indies first innings of 299 .
alastair cook -lrb- 76 -rrb- and jonathan trott -lrb- 59 -rrb- put on an opening stand of 125 but could n't reach their centuries .
no 5 joe root was outstanding reaching a century at a strike rate of 80 and was 118 not out at stumps .
root 's half-century gave him an england record-equalling sixth test score of 50 or more - no-one has seven .
gary ballance was out softly for 77 after ian bell played on for one . moeen ali ran himself out for a duck .