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【单选题】
若 i 1 =10sin( ω t+30 ° )A , i 2 =20sin( ω t-10 ° )A ,则 i 1 的相位比 i 2 超前 。A.
20 °
B.
-20 °
C.
40 °
D.
-40 °
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皮皮学刷刷变学霸
举一反三
【单选题】(2012·昆明高二检测)It is well-known that proper amounts of exercises, if _______ regularly, will benefit our health.
A.
being carried out
B.
carrying out
C.
carried out
D.
to carry out
【简答题】Ben： 2
【简答题】某元件的导纳的有名值为 Y = G+jB ,当基准值取功率 S B ,电压为 U B ,则电导的标幺值为 。
【单选题】_____ a good trip last month? [ ]
A.
Did Ben have
B.
Does Ben have
C.
Is Ben having
D.
Did Ben has