Question:
Can I use a highlighter on my textbook while I study on chol hamoed?
Answer:
if it is a torah related subject and you fear you will forget it it is permitted, but if it is only a vocational course it is only perimtted if without it you will be jepordizing the grade.
Sources:
O:CH 545-9 SH"T end of siman 545, Zichron Shlomo, pg 76-77
