a disease difficult to cure ☊ 
bệnh nan y ☊ isn't difficult (at all) ☊ có khó gì ☊ hard, difficult work ☊ công việc khó nhọc ☊ to avoid the difficult and do the easy ☊ dễ làm khó bỏ ☊ full of obstacles and difficult of access ☊ hiểm trở ☊ important and very difficult of access ☊ hiểm yếu ☊ place full of obstacles and difficult of access ☊ hiểm địa ☊ to develop, utilize the highland or the difficult region ☊ khai sơn ☊ to spread widely; widespread, difficult to stop, rampant ☊ lan rộng ☊ very difficult to understand ☊ rất khó hiểu ☊ to be difficult to please ☊ vặn vẹo ☊ a very difficult thing ☊ điều vô cùng khó khan ☊ to place in a difficult situation ☊ đặt vào thế khó xử ☊ tide over the current difficult time ☊ đỡ thì ☊