At previous summits, the United States set forth an ambitious and still unattained goal: forging a vast, hemisphere-wide free-trade zone.

VOA: standard.2009.04.15

The other quick thing I want to say is that I do have office hours today from 3 to 5, so feel free to stop by if you have questions about problem-set 3 that you're finishing up.

我还想说一件小事,我今天的答疑时间是三点到五点，如果你对于第三次作业还有任何疑问,请在这个时间段来找我，不必客气。

麻省理工公开课 - 化学原理课程节选