He           very hard when he was a student.[ ]

A. study      

B. studied    

C. studies      

D. studying

读句子，回答问题。

    人人为我，我为人人。我觉得这一种境界是颇耐人寻味的。     

1．理解词语。    

      颇：                                                           

      耐人寻味：                                                              

2．“这一种境界”是指                                                                                                               

3．请你列举自己生活中“人人为我，我为人人”的事例。