When he first arrived at university, he was not sure whether he was supposed to scribble ______ every word out of the professor's mouth.

【正确答案】down

【答案解析】 句意：第一次上大学时，他不确定是不是应该把从教授嘴里说出来的每个字都草草地记下来。scribble down胡乱写下。