单项选择题
A generator is prevented from becoming motorized by the use of a/an （）.
A.over-speed trip B.reverse power relay C.back pressure trip D.governor controls
单项选择题 Which of the electrical properties listed will always be the same for each component in a parallel circuit?（）
单项选择题 A switchboard, for a AC electrical distribution system, will be provided with which of the following components （）.
单项选择题 The sub-multiple prefix “nano” (n) means （）.
