In my Rubiks World novel I have some sentences in passive voice. The word grammar checker always tells me to rewrite it in active voice. However I don't really think that in any of these cases it is wrong to use the passive voice and that in some it is wrong to use the active voice. Here are the sentences in passive voice: The control is done a little later than the conditionals. (This is related to the pregnancy and adult size control study) Every time something new is discovered in math and science or something new is made the cubes rotate jobs. (This is related to the empire that a group called "The Cubes" has formed) In the first one it is a compound subject with the 2 subjects being control and conditionals. I separated it with the passive "is done" because I wanted to compare the 2 time-wise. Plus this is a note about the study since this isn't your normal control study(where control and conditionals are done at the same time). Thus I don't think this is a grammar error. In the second one I think it is wrong to use the active voice since unless you know who discovered something you don't usually say "A discovered B" where A is someone that discovered something and B is the thing that was discovered but rather something like "B was discovered in C" where once again B is what was discovered and C is the time at which it was discovered or "B has been discovered". The second and third ones are in passive voice but the first one is in active voice. So should I change these sentences to active voice or just leave them in passive voice?