调节呼吸、心跳的重要生命中枢是（ ）
A：大脑
B：小脑
C：脊髓
D：脑干
《论语》里孔子曰：“见贤思齐焉，见不贤而内自省也。”你认为对这句话理解正确的是 （ ）
____ He's my brother.
____ Who's that boy?
____ Yes, she is.
____ Is she your mother?
____ No, he isn't. He's my teacher.
____ Is he your father?
把红、黄、蓝、白四种颜色的球各8个放到一个袋子里．至少要取（ ）个球，才可以保证取到两个颜色相同的球．
