属于非竞争性α受体阻断药的是
A.新斯的明
B.酚妥拉明
C.酚苄明
D.甲氧明
E.妥拉苏林
参考答案:C
已知xa=3,xb=5,则x2a+b=( )
The plant products have been carefully inspected and are considered to be ( ) from any quarantine pests.
A.outB.awayC.freeD.far