Hi Kohaku,
I have had the same experiences with my students. WHY involves higher-order thinking because a student has to understand cause, effect, consequences, and reasons for something in order to understand this. Your students probably feel that they don �t have the background to explain these kinds of relationships so I �d suggest the following
- teach them the common vocabulary to answer these questions: because, the cause is, A makes B happen, etc.
Not to advertise myself, but I prepared some worksheets on these things so check out some of my worksheets on eslprintables (cause and effect AND affect and influence)
- use graphic organizers to make sure that they understand these relationships and to help them organize their thoughts.
It will get easier in time! You just happen to be the teacher who is helping them transition into having this particular English skill!
Good luck and I hope I �ve suggested something of use to you!