维持正常呼吸节律的中枢部位有
A．脑桥呼吸调整中枢
B．大脑皮层
C．延髓呼吸中枢
D．脊髓呼吸中枢
参考答案：A,C
Since my childhood I have found that ________ is more attractive than reading, which is my favorite.
A．everything
B．nothing
C．something
D．anything
工业用水管线色标是（）。
A.黄色
B.红色
C.绿色
D.天蓝色
