为什么题目中mn等于3分之一，不应该大于1吗？

题目中为什么mn等于3分之一，不应该大于1吗？

devoted to his research work,the professor cared little about any other things. devoting to his research work,the professor cared little about any other things. 这两个句子那个正确？

judged from her last letter,they are having a wonderful time. judging by her last letter,they are having a wonderful time.

例5怎么做

【语法】After that ,I gave that had bought and another birthday care to the needy family.这里的that 为什么要改成what。