【简答题】改错。 1. Do you like music that make you excited? 2. Is this the topic that you talked about it yesterday? 3. That's the CD I have been looking forward. 4. The boy is sitting behind Nancy comes from Can...
【简答题】从B栏中找出适合A 栏中问句的相应答语。 A ( )1. How do you come to school? ( )2. What did you do yesterday? ( )3. How many pens do you have? ( )4. What will you do? ( )5. How much are they? B A. I we...
【简答题】一块厚0.025mm的方解石晶片,其光轴与表面平行,放置在两正交偏振片之间。从第一偏振片出来的线偏振光垂直入射到品片上,振动方向与晶片的光轴方向夹45°。求: (1)透过第二个偏振片的光在可见光谱(400~700nm)中缺少哪些波长? (2)若两偏振片的振动方向互相平行,则透射光中缺少哪些波长?假定双主折射率之差n o -n e =0.172可看作常数。