More than one third of all threatened or endangered bird species in America live on the Hawaiian Islands.

VOA: special.2009.05.12

And then there is this third species, the neutron, which has no charge.

这是第三种了，中子，不带电。

麻省理工公开课 - 固态化学导论课程节选

Vertebrate species,for example, decreased by nearly one-third between nineteen seventy and two thousand six.

VOA: special.2010.05.25