This is the same basic system used today , the only difference being that instead of the subscript number used today -LRB- e.g. , H2O -RRB- , PERSON@1 used a superscript -LRB- H2O -RRB- .

This is the same basic system used today . The only difference is that instead of the subscript number used today -LRB- for example , H2O -RRB- , PERSON@1 used a superscript .
