If it is voluntary, it shows that children still prefer liberal arts, so there is still much room for improvement if they work hard to stabilize their mentality.
If parents choose for their children, then children may be rebellious and have poor grades. If parents still insist on letting their children do things that children don't like, it will take great efforts to improve their grades.
Anyway, guide the children to study hard first. If it is really difficult to learn, you can also find a local counseling agency to help your child. It is suggested that you can make a plan for your child's further education in advance. There are still many schemes for students with low scores to enter ideal undergraduate colleges. Planning ahead will get twice the result with half the effort.