In order to catch up with her classmates .A. a lot of books were bought by Mary’s motherB

问题补充：

In order to catch up with her classmates, .

A. a lot of books were bought by Mary’s mother

B. Mary’s father helped her with her lessons

C. Mary worked hard at her lessons around the clock

D. Mary’s classmates helped her a lot

答案：

A. a lot of books were bought by Mary’s mother

B. Mary’s father helped her with her lessons

(答案→)C. Mary worked hard at her lessons around the clock

D. Mary’s classmates helped her a lot

解析：考察不定式用法。本题中的不定式在句中做目的状语，其逻辑主语要是句子的主语。In order to do catch up with…的逻辑主语是Mary。句义：为了赶上她的同学，Mary通宵地认真学习。故C正确。