to narrow down sth or to narrow sth down缩减;限制;缩小
They narrowed the choice down to about a dozen.他们将选择范围缩小到了十来个。
How can you narrow down over 30,000 course possibilities to just one?怎样才能从3万多门可选课程中敲定1个呢?
I've narrowed the list down to three.我已经将名单缩减为3人。