1-A； Two-dimensional; Three dimensions; 4-B； 5-C； 6-D；

In view of space, only error 2 and error 6 will be explained.

2. a>b, both sides are multiplied by a positive number C, and the directions of unequal symbols remain unchanged, so D is correct.

When the signs of A and B are the same and not zero, A is also correct; But when a is positive, b is negative, or 1 is zero,1/a.

6.m is perpendicular to plane a and straight line n, and there are two possibilities: n//a, or n is on plane a, so c is incorrect.

But m is perpendicular to two different planes at the same time, so the two planes are parallel, so d is correct.

The photos sent are comprehensive training topics. Although asking for help can get the right result, you need to think, practice, master what you have learned, and then use it flexibly. I hope you can grasp yourself and strive for good academic performance with your own efforts. I wish you progress in your study!