Soldiers have launched a massive rescue operation. The army has a heavy presence in the area, which shares a border with China.

VOA: standard.2010.08.06

So iron left to own devices in the atmosphere in the presence of a little bit of water, with the water form iron oxide.

铁在大气中，在存在,少量水的条件下，大气会开始与水结合产生氧化铁。

麻省理工公开课 - 热力学与动力学课程节选

It's with this image of a brooding impregnation that Milton announces the presence in his poem of his most potent, what I think is the most interesting, theological innovation that he comes up with here.

正是通过这个孵伏怀孕的形象,弥尔顿在这里宣告了他在这首诗中,最具潜力，最有趣的神学新观点。

耶鲁公开课 - 弥尔顿课程节选

If a ligand comes and interacts with a receptor, it opens up; In the presence of this ligand, if the ligand goes away, it closes.

如果配体与受体相互作用,在配体存在的情况下通道打开,如果配体脱离,通道就关闭

耶鲁公开课 - 生物医学工程探索课程节选