题目

At the conference, political leaders from many countries promised to work together to defend the world ________ terrorism and other threats. A . for B . without C . beyond D . against 答案：D11．下面各组对象中不能形成集合的是（　　）A．所有的直角三角形B．圆x2+y2=1上的所有点C．高一年级中家离学校很远的学生D．高一年级的班主任