If the operation ________ carefully prepared, it would not have been successful.
C
语法题：虚拟语气。
Ittookmeamonthtogetrid_______thecough.
Theprofessoraskedaquestion,andDavid________agoodanswer.
It took me a month to get rid _______ the cough.
Heblamedhispoorperformance_____jetlag.
He would have given you more help, if he ________ so busy.