Even though there is plenty of evidence that the quality of the teachers is the most important variable, teachers' unions have fought against getting rid of bad ones and promoting good ones.
尽管有大量证据表明教师素质是最重要的变量，但教师工会却反对淘汰不合格的教师和提升优秀教师。
They rid the forest of dead and sick trees, reducing competition and curbing the spread of disease.
它们清除了森林中的枯死和病弱树木，减少了竞争并遏制了疾病的传播。
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。