4 \u201ck\u1ebb th\u00f9 t\u00e2m l\u00fd\u201d c\u1ee7a h\u1ecdc sinh tr\u01b0\u1edbc k\u1ef3 thi v\u00e0 c\u00e1ch \u1ee9ng ph\u00f3<\/a><\/blockquote><\/iframe>