[tag=DT] [lemma=means] [word=a] [lemma=total] [□=□]
[tag=DT] [lemma=means] [word=a] [lemma=total] [lemma=□]
[tag=DT] [lemma=means] [word=a] [lemma=total] [tag=□]
This means a total of at least seven years of previous preparation .