变频器主电路中指示灯的作用？
参考答案：
①指示电源；②变频器内的电容内有电；③指示灯灭后变频器才安全；
— Would you like______, sir?
— No, thanks. I have had much. [ ]
A. some more oranges
B. any more oranges
C. some more orange
D. any more orange
关于泪液中离子浓度，正确的是
A．C1-浓度低于血浆浓度B．K+浓度低于血浆浓度C．Na+浓度高于血浆浓度D．Mg+浓度高于血浆浓度E．Ca+浓度低于血浆浓度
