Entire sections of Washington have been on virtual lock-down in advance of the summit.

VOA: standard.2010.04.11

And then we'll see exactly what it is that he's doing here so we're going to try to lock in on the bass.

现在我们来听一下这首歌究竟是什么样的，然后我们来尝试专攻它的低音部分。

耶鲁公开课 - 聆听音乐课程节选