It seems that teachers in some countries are telling their students to fill their answers with "difficult grammar devices" like passives, conditionals and subjunctives.
I tell my students to do the opposite: forget about these things!
In my experience, the more you focus on grammar (25% of your score), the less you focus on answering the question well, organising your ideas, and using good vocabulary (75% of your score). Worrying about "difficult grammar" is likely to ruin your answers rather than improve them! Focus on the other 75%.