Extremely cold weather in Europe

Analysis of test questions: the query and cause analysis of global warming show that people's understanding is repeated and D is correct; The understanding of global warming cannot be called truth, so AC does not match the meaning of the question; There is a strict boundary between true and false, and B is wrong.

Comments: Based on some scientists' doubts about global warming, this question examines students' understanding and application of cognitive characteristics, and requires students to accurately interpret and understand the content of the options and accurately grasp the main idea of the materials. The difficulty is moderate.