并联运行变压器的短路电压比应不超过()。
A.±5%
B.±8%
C.±10%
D.±15%
参考答案:C
酚妥拉明兴奋心脏的机制是()
A.直接兴奋心肌细胞
B.反射性兴奋交感神经
C.直接兴奋心脏的β1受体
D.阻断心脏的M受体
E.直接兴奋交感神经中枢
It seems that living green is ______ easy and cheap. A small step can be rewarded with long-term benefits.
A.astonishingly
B.exactly
C.fortunately
D.hardly