Final answer:
The best word to complete the sentence is 'comprendí', which means 'I understood' in English.
Step-by-step explanation:
The best Spanish word to complete the sentence 'Yo ________ la lección' is 'comprendí'.
'Comprendí' is the past tense form of the verb 'comprender', which means 'to understand'. It agrees with the subject 'yo' (I) in the first person singular.
For example, if the sentence were 'Él/ella/usted comprendió la lección', the correct word would be 'comprendió'.
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