narrow down
phrasal verbnarrow something down (to something)
to reduce the number of possibilities or choices 把（可能性或选择）缩小（到）；缩小范围 We narrowed the choices down to five categories. 我们把选择范围缩小到五个类别。 the following list may help narrow down the cause of the problem. 以下列表可能有助于缩小问题的原因。 We have narrowed down the list to four candidates. 我们把范围缩小到四位候选者。