You must take everything into when you want to do a difficult task.
A. observation
B. regard
C. count
D. consideration
网友回答
A. observation
B. regard
C. count
(答案→)D. consideration
解析：考查固定短语。take sth. into consideration“考虑某事”。句意“当要完成一项艰难的任务时，你必须全面考虑一切。”故选D。