[lemma=source] [tag=IN] □ □
[lemma=source] [tag=IN] [□] □
[lemma=source] [tag=IN] □* □
After this , it is some relief to know that they had but one b , one p , and one f. All these letters must have stood originally for monosyllabic words belonging to the earliest stage of the language ; but it is no longer possible to identify the source of every letter , owing , doubtless , to the fact that many of the oldest words had become obsolete by the time when the alphabet had reached that point of development at which our knowledge of it begins . The optimizer joins every row from one data source with every row from the other data source , creating the Cartesian product of the two sets . " Christ is the source of every right impulse . These booklets are not intended to replace the teaching of the TEKS curriculum , provide the basis for the isolated teaching of skills in the form of narrow test preparation , or serve as the single information source about every aspect of the TAKS program .