肾动脉狭窄患者应禁用:()
A.血管紧张素转换酶抑制剂
B.钙通道阻滞剂
C.β受体阻滞剂
D.α受体阻滞剂
E.中枢交感神经抑制剂
参考答案:A
American English has so many ______ because the American people have come from all over the world. [ ]
A. grammar
B. vocabulary
C. pronunciations
D. dialects
铝管焊接前可采用车、锉等方法开坡口,然后再进行焊接。