Spanish uses definite articles much more than we do in English, such as this phrase from lesson 15.4:
“Y mi palabra es la ley.”
"And my word is law."
Another example (my own construction):
"I began the flash cards for lesson 15.4"
"Comencé las tarjetas de memoria por la lección 15.4"
The use of definite articles seems a bit inconsistent and arbitrary in sentences such as these. It seems that, most times, using the definite article is correct even when not used in the corresponding English sentence, but other times it is not used in a sentence of the same basic construction.
Has anyone else encountered this inconsistency, or am I missing a basic rule of Spanish grammar here? Or is truly optional and either construction is correct?