V\u0103n m\u1eabu t\u1eadp 1: Ph\u00e2n t\u00edch \u0111o\u1ea1n tr\u00edch T\u00ecnh y\u00eau v\u00e0 th\u00f9 h\u1eadn (B\u00e0i 2)<\/a><\/blockquote><\/iframe>