—We hope to help poor children without enough food.
—You set up a food bank.
A:must
B:could
C:need
D:have to
—Do you want to keep goldfish?
—No, they are ______ difficult for me______ take care of.
如图,已知三角形ABC的边AB是⊙0的切线,切点为B.AC经过圆心0并与圆相交于点D、C,过C作直线CE丄AB,交AB的延长线于点E.
(1)求证:CB平分∠ACE;
(2)若BE=3,CE=4,求⊙O的半径.
图为中国农作物分布,读图完成下列问题.