Final answer:
The best Spanish word to complete the sentence is 'hablándoles'. It means 'speaking to them' and is the gerund form of the verb 'hablar'.
Step-by-step explanation:
The best Spanish word to complete the sentence is hablándoles.
This word is the gerund form of the verb 'hablar' which means 'to speak' in English. It is used to indicate an ongoing action. In this sentence, it is showing that the teacher is speaking to them.
For example, you could say 'La maestra está hablándoles a los estudiantes' which means 'The teacher is speaking to the students.'.
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