① ____     A. cold

② ____     B. outside

③ ____     C. hot

④ ____     D. inside

The part in the film Rio _______ the two birds escaped from the crashing plane made some of the audience give a cry.

①有利于增强未成年人的安全意识和自我保护能力

②有利于建设安全和谐的校园

③有利于未成年人掌握必要的安全知识和技能

④能完全避免未成年人意外伤害事件的发生

若△ABC的三个内角A、B、C成等差数列，则$\cos \left(A+C\right)=$(    )