【简答题】In the lecture, the professor describes the main characteristics of white and black dwarfs. Indicate which of the following corresponds to either category of star. Click in the correct box for each ph...
【单选题】听力原文:M: Where's Professor White this morning? W: He's a little under the weather. He got soaked in the heavy rain the night before last and you know his health. Q: What does the woman say about Profes...