【单选题】光导纤维被认为是 20 世纪最伟大的发明之一,它使信息高速公路在全球迅猛发展,它的发明者是被誉为 “ 光纤之父 ” 的华人科学家高锟。光导纤维 的主要成 分是 A . Si B . SiO 2 C . Na 2 SiO 3 D . Si Cl 4
【单选题】Mike likes reading English __________. He also likes to do __________ English exercises. [ ]
【单选题】Dick and Bob are classmates. Dick likes reading novels after school, _______ Bob likes basketball.
【单选题】单项选择。 Kelly likes ______. [ ]
【单选题】Paul is his mother. He reading, too.
【单选题】下列哪种情况可以使回路总电势不为零:( )
【单选题】光导纤维被认为是20世纪最伟大的发明之一,它使信息高速公路在全球迅猛发展,它的发明者是被誉为“光纤之父”的华人科学家高锟.光导纤维的主要成分是( )