(1) Christopher Columbus discovered America in 1492, though he mistakenly thought he had reached India. (2) In the 1770s, the 13 American colonies had 2.5 million residents, and during the first winter, half of them died. (3) George Washington was the commander-in-chief of the Continental Army and later became the first president of the USA. (4) The official language of the USA is American English, and Independence Day is celebrated on July 4th.