5PHRASAL VERB 使(新产品)经使用逐渐合用;磨合 If you break in something new, you gradually use or wear it for longer and longer periods until it is ready to be used or worn all the time. 使(新产品)经使用逐渐合用;磨合 [Also VERB n PREPOSITION]
When breaking in an engine, you probably should refrain from high speed for the first thousand miles. [VERBPREP. noun]
当磨合发动机时,最初的1,000英里里程内尽量不要高速行驶。
Nathan's new running shoes weren't broken in correctly. [VERBPREP. noun (not pronoun)]