一块椎骨的椎体和椎弓围成
A．骶管裂孔B．椎管C．骶管D．椎孔E．椎间孔
参考答案：D
解析：椎体与椎弓围成椎孔。
—Please say something about Zheng He.
—Oh! He is the Ming dynasty explorer of ______ all the Chinese are proud.
A．who
B．whom
C．whose
D．that
实际的制冷压缩机的气缸没有余隙容积。
