【单选题】A disk is rotating about its central axis like a merry-go-round (旋转木马) . The angular position θ (t) of a reference line on the disk is given by θ = -1.00 – 0.60 t + 0.25 t 2 . At what time t min does ...
【简答题】听下面一段对话,回答第1-2题。 1. What time is it now? A. 9: 30. B. 9: 15. C. 8: 45. 2. Why does Tony want to go to school? A. He loves studying very much. B. He can play with many friends. C. He wants to have a go...