I regret _____ hard at school, or I would have succeeded in passing the exam.

   　A. not to work        

     B. having not worked  

     C. to have not worked  

     D. not having worked

The boy wanted to ride his bicycle in the street, but his mother told him _______.

A. not to 　 B. not to do

C. not do it 　 D. do not to

　　The boy wanted to ride his bicycle in the street, but his mother told him _______.

　　A. not to B. not to do C. not do it D. do not to

_____ how to express the idea in English, he turned to the dictionary.

　　A. Does not know　 B. Not knowing  C. Knowing not　　D. Not to know

Thinking about the fact that I was not prepared well enough,and _______ to lose my face,I gave up this year’s civil service exam.?

A. didn?t want B. not wanted?

C. not wanting　D. not to want?