小学科学课上，宋老师向学生们讲到电灯亮了时，说爱迪生经过一千多次的实验，终于把适合做灯丝的材料—钨丝找到了，同学们深受教育。这体现了哪一教学原则？（ ）

(单选题)Amy majors in Arts, ______ in her mother’s footsteps. (单选题)My computer had a ______ system because it ceased to functio (单选题)This new type of machine is said to be expensive but effecti (单选题)Jenny depicted Paris as a romantic and spectacular place, as (单选题)—What do you think of the bike you bought yesterday?—At leas (单选题)Its website says the center is a living history museum _____ (单选题)So far economic and technological changes ______ shifts in t (单选题)Fifty days ______ like a long period for me to wait for the (单选题)Though he is always odd, we can’t ______ his accomplishments (单选题)People who live in the northern U.S. are more generous with