Y/Δ-11接线变压器的零序阻抗测量计算公式为（）。
A.U0/3I0
B.3U0/I0
C.U0/I0
D.I0/U0
参考答案：B
It is said that the corporation in______charge of him is in______debt now.
A．the;the
B．/；/
C．/；the
D．the;/
当时角t。=60°时，日长为（）小时.
