Question

If you are going to the concert, you should buy tickets in advance. (Points : 2) advance tickets should be bought tickets should be bought in advance tickets should have been bought in advance should buy advance tickets No improvement or correction is required.

Answer 1

This is an arguable question because I believe there could be two answers.
On one hand, the sentence above is correct the way it is, and no improvement or correction is required. To buy tickets in advance means to buy them before going to the concert. On the other hand, you can also say - tickets should be bought in advance - both options are correct. However, if you have to choose only one, I'd go with - no improvement or correction is required.