Final answer:
The correct frequency word to complete the sentence is 'Nunca' which means 'Never' in English.
Step-by-step explanation:
The correct frequency word or phrase to complete the sentence is Nunca. The sentence translates to 'I mow the lawn because I don't have a garden.' Since the speaker does not have a garden, they never mow the lawn. Therefore, the word 'Nunca' which means 'Never' is the best choice.
Learn more about Frequency words in Spanish