He was sitting there ________ his cigarette. Without any words, he seemed to be ________ deep

thought.   [ ]

A. at; in        

B. over; in        

C. with; at      

D. with; over

在日常生活中，践行敬业精神要求从业者必须()

A.公私分明 

B.坚守工作岗位 

C.提高职业技能 

D.强化职业责任