In response to the argument that the global warming trend has changed, experts pointed out that the extremely cold weather that has occurred frequently around the world since last winter is a normal p

In response to the argument that the global warming trend has changed, experts pointed out that the extremely cold weather that has occurred frequently around the world since last winter is a normal phenomenon in the process of global warming. C

There is no essential change in the long-term trend of climate warming, which shows that we should grasp the internal essential relationship of things through phenomena. This judgment is based on a long time scale, which shows that knowledge is constantly tested by the practice of change and development, so C.①④ is chosen. The material is not talking about the ready-made conclusions drawn from timely revision of understanding and respect for expert authority.