人教课标 高一 必修 3 Unit 4Rewrite the following sentences with noun clauses as the subject. 1. His discovery has not yet been proved. 2. Do the other astronomers accept his ideas? It remains a question.What has not yet been proved is his discovery. Whether the other astronomers accepts his ideas remains a question.3. The first appearance of life on earth is still a mystery to scientists. 4. Why is the earth becoming warmer? It is an important topic for research.How life first appeared on earth is still
