1) bai pho tu'

   mondai4: 1. 4; 2. 1; 3.4; 4.3; 5.2; 6.4; 7.1; 8.2; 9.4; 10.4

2) chi thi tu

   mondai1: 1.c; 2.d              mondai2: 2 (bunmyaku shịjino yoohoo)