(a) free rein complete freedom of action or expression.
☞ The image here is of loosening grip on the reins of a horse, allowing it to choose its own course and pace, in contrast to the greater control implied by the next idiom.
英语词组固定搭配大全包含15956条英汉双解词组,基本涵盖了全部常用英文词组、短语的翻译及用法,是英语学习的有利工具。