—Of course. After hearing the good news, the whole school shouted with joy.
A:happiness
B:kindness
C:sadness
已知AB是⊙O的弦,AB=8cm,OC⊥AB与C,OC=3cm,则⊙O的半径为____cm
Be careful your things. Don't lose them.
下列哪一种疾病不属于遗传病( )