Because they don't want to just students abstain from Yong, but PC questions for more, they must learn that both konnak and morality. So these ด็ก has grown to become citizens, the quality of the next country.
Because they did not want students just as good, just as they must, and students at all good and virtuous. The child will not grow up to be citizens of the country.
Because they didn"t want to just the students with good ดพี only but they need the students ที่ทั้ง ability and virtue. To ที่ด็ these will grow up to be a citizen quality of countries.