题目

—I haven't seen Jack for two days. Is he ill? —________.The head teacher said that he was in hospital. A . I'm afraid so B . I'm afraid not C . I hope not D . I'm glad to hear that 答案：A已知m，n是两条不同的直线，α，β是两个不同的平面，给出下列命题：①若m∥α，n∥β，且m∥n，则α∥β；②若m∥α，α⊥β，则m⊥β；③若m⊥α，n⊥β，且m⊥n，则α⊥β；④若m∥α，m⊥β，则α⊥β.其中正确命题的序号是(　　)A. ①④ B. ②③C. ②④ D. ③④