所有交、直流电焊机及水泵的外壳,都必须采取保护接地或接零。接地、接零电阻值应不小于()Ω。
A.4
B.10
C.0.5
参考答案:C
缺词填空。
Today is Jack’s birthday. He 1. l_____ cool in a new shirt and a pair of
2. j_____. 3. T_____ some drinks and food on the table. His friends have
4. l_____ of birthday gifts (礼物) 5. f_____ him---CDs, chocolate, toys and
6. c_____ books. He is glad to see so many nice things. Some 7. o_____ his
friends stand beside the table and 8. s_____ the nice food with him. Some sit on
the sofa and chat with each 9. o_____. Everyone has fun at the 10. p_____.
猩红热的主要病机是()。
A.痧毒疫疠蕴于肺胃
B.麻疹热毒犯于肺卫
C.麻疹热毒蕴于脾胃
D.痧毒疫疠侵犯肝胆
E.以上都不是