Farmers may think trees will take too long to grow and be effective.

VOA: special.2009.09.08

But what you should be able to do is take a look at a list of answers for what we're saying z effective might be, and determining which ones are possible versus which ones are not possible.

但是你们应该能够做到的,是看一下这个可能的,有效电荷量的答案列表，并且确定哪些是可能的,哪些是不可能的。

麻省理工公开课 - 化学原理课程节选

The White House says it is preparing for the worst. Experts say the most effective solution involves drilling relief wells to reroute oil, a process that could take months.

VOA: standard.2010.05.31