设A,B,C为三个随机事件 ,且P(A)=P(B)=P(C)=1/4,P(AB)=0,P(AC)=P(BC)=1/12,则A,B,C中恰有一个事件发生的概率为()
D
In the future, more ______ should be placed on the education of the young.
Night ________ (fall), we hurried home.
Only when you have obtained sufficient data ________ come to a sound conclusion.
1953 年，为解决粮食供应紧张问题，我国采取的新措施是 ()
设A，B=,则A与B=（）
