S 2. 开发地区的边缘,边远地区 the border between settled and wild country
P 3. 尚待开发的领域 a border between what is known and what is unknown
词汇搭配
动词+～
close a frontier 关闭边境
～+介词
the frontier between 在…之间的界线
have frontiers with 与…接壤
句型例句
There have been large-scale military manoeuvres on the frontier.边境地区曾有过大规模的军事演习。
Areas near the frontier were rough and lawless in the old days.过去边远地区混乱不堪,而且没有法律。
They are highly interested in the frontiers of science.他们对于科学的新领域有浓厚的兴趣。
