Betty enjoys playing ______ piano while her brother lovers playing ______ basketball.
A:the; a
B:a; the
C:/; the
D:the; /
逆反心理对我们的学习极为不利,对我们的身心健康发展也非常有害。( )
阅读下文,回答相关问题。
求证:OC是∠AOB的平分线.