Afghan President Hamid Karzai and Pakistani President Asif Ali Zardari flew into Tehran, at the head of high-level delegations, to discuss a series of problems, including drugs, terrorism and Islamic extremism.

VOA: standard.2009.05.24

And they were kind enough to send us this magnetic tank which we'll call forth from the computer solutions to a series of problems that would occur on a simulated flight to the planet Saturn.

他们很友善，送给我们这个有磁性的水槽,用于计算机解决一系列,土星模拟飞行中,可能出现的问题。

哈佛公开课 - 计算机科学课程节选