【多选题】What are the reasons for students' language deficit?
A.
Students are not stupid. However, they mistakenly learn whatever they see and hear in their language environment.
B.
Schools fail to establish high standards of English language abilities.
C.
Schools are unable to sufficiently teach the basic concepts of language-grammar and vocabulary.
D.
Young teachers know little about these important structures of language since they also didn't have the chance to deal with them in their prior learning experience.