题干
As a teacher, you shouldn't _________ those students who behave badly in school. What you should do is help and love them.
A：look forward to
B：look up to
C：look back on
D：look down upon
答案(点此获取答案解析）
D
，将
的图象上各点的横坐标缩短为原
，纵坐标不变，再将所得图象向右平移
个单位，得到函数
的图象，则函数