①真理并不确定,因为它是具体的有条件的
②实践是认识的和认识发展的动力
③认识反作用于实践并决定实践的发展
④实践是人有意识有目的能动性活动
A:①②
B:①③
C:②④
D:③④
0.32×500=____ 34+18 = ____
1- 712 =____ 2.8×0.4=____
150÷0.75=____
如图,在方格纸中,△ABC和△EPD的顶点均在格点上,要使△ABC∽△EPD,则点P所在的格点为____ .
若a→=(1,1),b→=(1,-1),c→=(-1,2),则c→等于( )
The s____ between the two reports suggests that one person wrote both.