如何使用 "keystone" 造句

1. Transcanada is the company constructing keystone .
横加公司是公司建设重点
2. 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。
3. 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。