It is not, however, a sign that they're getting serious about transforming the postal system for the 21st century.
然而，这并不是一个迹象，表明他们正认真致力于为21世纪改造邮政系统。
Solar panels had a few niche uses until they became cheap; now they are transforming the global energy system.
太阳能板在变得便宜之前只有少数利基用途；如今它们正在改变全球能源系统。
例句取自历年考研英语真题，翻译为机器生成，仅供学习参考。