A:磁卡和VCD光碟都采用了磁性材料
B:光纤通信是利用激光在光导纤维中传播
C:LED灯采用的是半导体材料
D:超导材料可用来做电动机的线圈
— Have you seen the film called The trouble with Teenagers?
—Yes, but I don't think it is worth _______.
“每个人都有他的隐藏的精华,和任何别人的精华不同,它使人具有自己的气味。”法国作家罗曼•罗兰的这句话告诉我们( )
— I to school at eight. What about your brother?
—He to school at seven thirty.
赛龙舟是端午节重要的民俗活动之一.赛龙舟时,调节选手动作协调有序的系统是( )