A:R1=9.5kΩ R2=90kΩ
B:R1=10kΩ R2=100kΩ
C:R1=10kΩ R2=90kΩ
D:R1=9.5kΩ R2=99.5kΩ
太阳光球层和色球层分别出现的太阳活动主要标志是( )
We had a great time in the water.