GMAT Verbal & Essays

Hi guys, i am not a native test taker. So SC is the most dreading part for me. As the test is adaptive if I get RC or CR in the first place then I think I will get difficulty level questions soon but this scenario may not applicable for SC. So my query is, will I almost always face SC at first or is there any pattern for appearing SC,RC& CR in the starting point? I have heard that the questions for RC is same for all test takers who get that. My question is if the questions don't change how will it be adaptive?

In my practicing of SC, I have found three level of questions-
1. Primary level- easily recognized error in sentence.
2. Intermediate level- The error is presented in a quite disguised manner.
3. Advance level- The error is presented with full disguised manner.
I have some problems for the last level. I have also found that I get confuse between two choices to get the right one in this level. How can I improve in this area?
The above findings are based on OG experience. Does OG enough to get all representative questions in the real GMAT for SC? Please help me.

Yes the way you have put it, you are using subjective.
Whats disguised to one may not be disguised to the other.
However, I have noticed similar issues.

SC is also mathematical in the sense, tense and verb form needs
to match.