例301　Additional social stresses may also occur because of the population explosion or problems arising from mass migration movements—themselves made relatively easy nowadays by modern means of transport.

【结构分析】句子的主干是Additional social stresses may also occur，后面的状语是because of the population explosion or problems，里面加上分词定语arising from mass migration movements，破折号后面是补充说明，是themselves，后面加上分词定语made relatively easy nowadays by modern means of transport。

【亮点回放】此句话的亮点在于两个超级的分词定语，分别修饰前面的名词，分词短语有时比定语从句，更加有特色，很有魅力。

【核心词汇】

additional social stresses　额外的社会压力

population explosion　人口爆炸

arise from　起源于

mass migration movements　大规模人口迁徙

by modern means of transport　通过现代化的交通方式

【参考译文】大规模的人口迁徙可以通过现代化的交通方式来实现，这种大规模人口迁徙导致了人口剧烈增长和相应问题的出现，额外的社会压力也会出现。