Final answer:
The correct word to use in this sentence is 'then'. 'Then' is used to indicate the sequence of events or the time that follows something.
Step-by-step explanation:
The correct word to use in this sentence is then. 'Then' is used to indicate the sequence of events or the time that follows something. In this case, Kevin asked the student a question and then someone interrupted the student when they tried to answer. On the other hand, 'than' is used for making comparisons.
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