供应链的水平结构是指跨越供应链的层次数目。
参考答案：对
改错。
( ) 1. We get to Harbin yesterday. _______________
A B C
( ) 2. People didn't went to the gym. _______________
( ) 3. You were very loudly! _______________
( ) 4. I went there on train. _______________
酚妥拉明扩张血管的原理是( )
A．单纯阻断。受体B．兴奋M受体C．兴奋β受体D．阻断α1受体，并直接扩张血管E．以上都不是
