如图所示为两个用摩擦传动的轮子，A为主动轮，已知A,B轮的半径比为R₁：R₂=1：2，C点离圆心的距离为 $\frac{R_2}{2}$ ，轮子A和B通过摩擦的传动不打滑，则在两轮子做匀速圆周运动的过程中，以下关于两轮缘上A、B点及C点的线速度大小V、角速度大小ω、转速n之间关系的判断中正确的是（   ）

当a=8，b=6时，2a+3b等于（        )

中国与东盟在经济上的互补性体现在（   ）

判断下列句子是否正确,正确的写“正确”,错误的写“错误”

    The school library opening time is from 8: 00 to 16: 00. Students must remember （记住）that they must not bring food and drinks into the library. They can take out six books every time. And they can only keep them for one week. If they don't give back the books on time, they'll have to pay（支付） some money. Students must take care of all the books. But some books are only for teachers.