复数： keystones
易混淆的单词： Keystone

Transcanada is the company constructing keystone .

横加公司是公司建设重点

They 're what ecologists call a " keystone " species , who control the abundance every other species , but require a habitat of sufficient size to support those other creatures .

它们是生态学家所谓的“重点”物种，控制着大量的其它物种，不过它们需要足够大的栖息地以供养其它那些生物。

However , these reserve requirements were abolished by margaret thatcher in 1980 as a keystone in her free market revolution , so that by the late 1980s every control and regulation on city lending had been scrapped .

然而，在1980年，作为撒切尔夫人自由市场改革的重点措施之一，这些存款准备金已经被废止，因此，到20世纪80年代末每一次城市的贷款的管制都被取消了。