已知抛物线y₁=a₁x²+b₁x+c₁，y₂=a₂x²+b₂x+c₂，且满足$\frac{a_1}{a_2}$＝$\frac{b_1}{b_2}$＝$\frac{c_1}{c_2}$=k(k≠0，1)．则称抛物线y₁，y₂互为“友好抛物线”，则下列关于“友好抛物线”的说法不正确的是（　　）

如图所示，几何体的俯视图是（   ）
 

You can ride your bike to school, but remember to be careful ____ .　　

This magazine isn't popular with the students though it____  every week.

It's difficult____  both the old and the young about the program at the same time.

The kids clapped and shouted ____ when the actor appeared.

Though he is very busy, he goes to the movies to relax____ 

The children are interested in playing the piano, so they need more____ 

The visitors ____  not to swim in this river for several times.

There are no students in the classroom. They ____  on the playground.

Thank you for____  the museum. We've learned a lot.

You must do more exercise, ____  twice a week.