(单选题)1: 电气化铁路采用的是工频单相（ ）kV交流。
A: 10
B: 20
C: 25
D: 30
1.(单选题)若集合A＝{a，{a}，{1，2}}，则下列表述正确的是()． A.{a，{a}}A B.{1，2}...
1.(单选题)—Howoftendoyougodancing — A.I will go dancing tomorrow. B.Yesterday....
1.(单选题)—Howlongisthiscellphoneguaranteed —______ A.No problem. B.You can re...
1.(单选题)—Wouldyouliketogotoattendtheconferenceonglobalwarmingwithme —______,...
1.(单选题)—Whatisthetrainingabout —_______ A.It is about the latest flood-proo...
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