①传统文化是维系民族生存与发展的精神纽带
②传统文化具有相对的稳定性
③传统文化应与时俱进
④应该摒弃传统习俗,创造新文化
A:①④
B:①③
C:②③
D:②④
阅读短文,下列问题
B
Amy
I like singing. I can play the guitar and the piano. I want to join the music club.
Bill
Do you want to know my favorite sport? I like playing basketball very much.
I can playing it well.
Jackie
I like playing the piano very much. I often play the piano after school.
Frank
My favorite sport is playing soccer, and I’m good at it.
①在天平两边托盘上各放一张质量、大小相同的白纸 ②将20g砝码放在左盘 ③将20g砝码放在右盘
④将游码拨至0.5g处 ⑤在右盘添加食盐至天平平衡 ⑥在左盘添加食盐至天平平衡.
已知圆x2+y2+8x﹣4y=0与圆x2+y2=20关于直线y=kx+b对称,
(1)求k、b的值;
(2)若这时两圆的交点为A、B,求∠AOB的度数.