After two years of hard work, the group paid for the solar panels, which now satisfy one-fourth of the school's electricity needs—saving the neighborhood thousands of dollars.
经过两年的努力，该组织购买了太阳能电池板，现在满足了学校四分之一的电力需求，为社区节省了数千美元。
3
It has been estimated that an additional one-fourth of the Earth's land surface is threatened by this process.