The origin of two is company, three is a crowd A company consisting of three is worth nothing It is the Spanish opinion who say that to keep a secret three are too many, and to be merry they are too few John Collins provides this translation which resembles more closely the English proverb (1834) “Three persons in company are too many for any secret affair, and two few for social
of the three vs of all three - English Language Usage Stack Exchange Both are correct You would usually use "A is the oldest of the three" if you were talking about three people from a larger group e g three girls who have two brothers, while you would use "A is the oldest of all three" if there were only three in the group e g three girls with no brothers
Why is it three score years and ten almost half the time and not . . . 3 Why is it 'three score years and ten' almost half the time and not always 'three score and ten years'? Note: I edited the question body and title in light of comments and answers pointing me to a Google phrase frequency chart which indicates that the two versions are used about equally often right now