Generally speaking, when marking papers online, draw the math drawing questions with 2B pencil first, and then use 0.5mm black neutral strokes again, so as to keep the drawing traces. (Because pencil drawings can't clearly show traces when scanned by computer)
Judging from the current situation, many local senior high school entrance examinations are marked online, that is, multiple-choice questions are marked by machines, and non-multiple-choice questions are marked online by teachers.