单相全控桥反电动势负载电路中，当控制角α大于不导电角δ时，晶闸管的导通角θ=（）。
A.π-α
B.π+α
C.π-δ-α
D.π+δ-α
参考答案：C
In the United States, the black people are often referred to as ______ in which the colour of their skin that caused them troubles and sufferings is NOT mentioned in English euphemisms. （ ）
A．niggers
B．negroes
C．the black
D．African Americans
为限制500kV线路的潜供电流，可采取下列哪些措施？（）
A.高压并联电抗器中性点接小电抗
B.快速单相接地开关
C.装设良导体架空地线
D.线路断路器装设合闸电阻
