1848年,两位伟人共同发表了国际工人运动的第一个战斗纲领《 * * 党宣言》,这标志着
A.空想社会主义的诞
B.列宁主义的诞生
C.自由主义的诞生
D.马克思主义的诞生
答案:D
单相全波整流输出电压峰值V1与交流输入峰值V2的关系是()
A.Vl>V2
B.Vl
C.Vl≈V2
D.Vl=1.4V2
E.V2=1.4V1
Mrs. Brown isn't here. She has to ______ her baby at home. [ ]
A. look at
B. look for
C. look like
D. look after