单项选择题
The sub-multiple prefix "milli" (m) means （）.
A.one thousandth (10 to the -3rd power) B.one millionth ( 10 to the -6th power) C.one billionth ( 10 to the -9th power) D.one trillionth (10 to the -12th power)
单项选择题 A “dead front” switchboard is one （）.
单项选择题 The total resistance of a parallel circuit is always （）.
单项选择题 Reduced voltage applied to a motor during the starting period will （）.
