Đăng bởi Hoàng Oanh
"vi-tri-dia-ly-trieu-tien"
"dac-diem-tu-nhien-trieu-tien"
"nen-kinh-te-trieu-tien"
"dan-so-cua-trieu-tien"
"phan-bo-do-tuoi-va-ty-le-gioi-tinh-cua-trieu-tien"
"cac-van-de-hien-tai-cua-trieu-tien"
"cac-su-that-thu-vi-ve-quoc-gia-trieu-tien"