“按完成任务的比率，排在前三名的是。。。”的翻译

According to proportion of the mission completed, the top three are...

According to the task-accomplished rate, the first three ones are...

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According to the task-fulfilled rate, the top theree are.....

按完成任务的比率，排在前三名的是 = According to the ratio (rate) of completion , the top (first) three in ranking are...

According to the proportion accomplishing a mission,arrange being before three. .