欧洲西部政治和经济联系密切的国际性组织是[ ]
A.欧佩克
B.国际奥委会
C.欧盟
D.世界贸易组织
答案:C
命题“若a>b,则2a>2b”的否命题为( )
A.若a>b,则有2a≤2b.
B.若a≤b,则有2a≤2b.
C.若a≤b,则有2a>2b.
D.若2a≤2b,则有a≤b.
all the required papers, he didn’t answer the questions fluently in class.
A.Having not read
B.Not having read
C.Not read
D.Not to read