When we talk about resonance structures, we're talking about cases that have the same arrangement of atoms the key is the atoms are the same, and the thing that is different is the arrangement of electrons here.

当我们讨论共振结构的时候，我们讨论的是原子排布相同情况,关键在于原子是相同的，不一样的只是电子排布。

麻省理工公开课 - 化学原理课程节选

Karzai and his Pakistani counterpart, President Asif Ali Zardari, are talking with key congressional leaders and policymakers ahead of meetings with President Obama and Clinton.

CNN: U.S. military: Taliban killings prompted airstrikes

I'm going to be talking about the key issues - jobs, health, education and running Wales well.

BBC: Blair back in Wales, backing Michael

One of the key talking points consistently mouthed by opponents of the Affordable Care Act is their declaration that the law wrests control of healthcare out from the hands of the consumer and places it squarely under the control of the federal government.

FORBES: Proof Obamacare Seeks To Put Control Of Healthcare In The Hands Of The Consumer