THEY ARE VERY PROUD ( ABOUT, OF, OFF, FOR ) THEIR CHILDREN.

3) - KIEM TRA 1 TIET ANH 8BAI SO 2HK IICO MA TRAN
KIEM TRA 1 TIET ANH 8BAI SO 2HK IICO MA TRAN

3) They are very proud ( about, of, off, for ) their children.