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