He sits me in the classroom. I can't see the blackboard clearly.
A:in front of
B:in the front of
C:at the back of
D:behind
下列各组物质中,前者为化合物,后者为混合物的是( )
定义在﹣2,2上的偶函数g(x),当x≥0时,g(x)单调递减,若g(1﹣m)<g(m),求m的取值范围.
①紫花×紫花→紫花
②紫花×紫花→301紫花+101白花
③紫花×白花→紫花
④紫花×白花→98紫花+107白花