A:人的意识能够决定客观事物产生
B:人的意识具有能动作用
C:人的认识能力是无限的
D:在一定条件下,意识可以先于物质产生
You may never be in an emergency situation. But if it happens, you should know how to get help. The telephone book in the United States has emergency numbers on the inside front cover. Look at the following table from the Boston telephone book. Notice that the numbers for the police and the fire department (部门) are the same. And it is an easy number to remember. If you are too unhappy or excited to remember any numbers at all, you can simply dial (拨打) “0” for an operator (接线员) in any emergency.
教师的教学方式各有特点,如果你对某一位老师的教学方式不太喜欢,你应该( )
Mg与NH4Cl溶液反应,除生成一种盐外,还有气泡产生。为确定气体的成分,进行下列实验探究:
【假设与猜想】气体可能是HCl,NH3,H2中的一种或几种。
【查阅资料】①NH3+HCl=NH4Cl ②2NH3+H2SO4=(NH4)2SO4
③2NH3+3CuO =△ 3Cu+N2+3H2O
类比平面内正三角形的“三边相等,三内角相等”的性质,可推出正四面体的下列性质,你认为比较恰当的是( )
①各棱长相等,同一顶点上的任两条棱的夹角都相等;
②各个面都是全等的正三角形,相邻两个面所成的二面角都相等;
③各面都是面积相等的三角形,同一顶点上的任两条棱的夹角都相等.