①是逆反心理,应任其自然发展
②是逆反心理,会给自己和家人带来伤害
③会影响家庭关系的和谐
④是品行恶劣的不健康的行为
A:①②
B:②③
C:③④
D:①④
They _______ in Shenzhen at that time(在那时). They were in Shanghai. ( )
若1<x<2,则x-3+x-12的值为( ).