题目

下列有关物质的用途，利用了物理性质的是（ ） A.稀有气体用来制作电光源      B.氮气用于填充灯泡 C.双氧水用于制氧气            D.漂白粉用于净水 答案：A— Jemmy likes to hang about in the street and doesn't do his job. — I _____ he will be dismissed by his boss. [     ]A. dare to say B. must say C. need to say D. dare say