Cac de thi nay c6 dap an hoac hudng dan tra Idi. Hgc sinh nang cao dugc ki nang renluyen thuc hien trgn ven mot de thi trong thai gian quy djnh; mot mat luyen kha nang giaibai tap, giai quyet van de, mat khac he thong hoa dugc cac kien thuc va ki nang can thietcho ki thi trung hgc pho thong quoc gia[r]