问答题 使用Powerpoint演播演示文稿要通过 [填空1]或[填空2]屏幕展现出来。

单项选择题 光纤是（ ）？ A. 玻璃材料 B. 碳纤维材料 C. 聚合物材料 D. 光导纤维

单项选择题 “It won’t be a crime。but it will certainly be a miracle”means“ ________ ”．A.Since no other persons are here，I wont’disclose(揭发)itB.It will certainly be a miracle if I don’t disclose itC.There isn’t any fish in the streamD.I will surely report you to the owner of the stream