合同可变更、撤销的前提是( )。
A.损害国家利益
B.违反法规
C.当事人提出请求
D.当事人一方违约
参考答案:C
解析:[知识点] 可变更或可撤销的合同
解不等式与解方程:
(1)4x2+(x-1)2>5(x-1)(x+1)
(2)2x(x+5)=x2+(x-2)(x+3)
Is there _____________in today's newspaper? [ ]
A. everything important
B. important nothing
C. anything important
D. important something