To learn a language, we need input (listening, reading) and output (writing, speaking) practice. We need the practice in two different ways: accuracy-focused (slow and careful, aimed at learning new words and grammar), and fluency-focused (quicker, less careful, practice things we already know for speed).
Unfortunately, in many senior high schools, most of the time is spent on accuracy-focused input, as you can see in the diagram above: in other words, students generally read difficult text, and try to learn lots of new vocabulary and grammar.