question: The invariant interval that separates two events in Minkowski spacetime can either be what ?
answer: space-like , light-like , or time-like
turker_answer: The invariant interval that separates two events in Minkowski spacetime can either be space-like , light-like , or time-like .
rule-based: The invariant interval that separates two events in Minkowski spacetime can either be space-like , light-like , or time-like .