合同无效的事由有
A.以欺诈手段订立合同
B.以胁迫手段订立合同
C.损害社会公共利益
D.恶意串通,损害第三人利益
E.以合法形式掩盖非法目的
参考答案:C,D,E
The summer is coming, _____ your sweater and _____ your T-shirt.[ ]
A. put on, take off
B. take off, put on
C. puts on, takes off
D. putting on, taking off
若误用500型万用表的直流电压250V档测量220V、50Hz的交流电,则指针指示在()位置。
A.220V
B.110V
C.0V
D.∞