Which is the only country in the South American mainland to have English as its official language?

Answer 1

Guyana
Britain took control of the area in 1796; Guyana became an independent dominion of the UK in 1966 and became a republic in early 1970. The Co-operative Republic of Guyana remains a member of the Commonwealth. The official language in Suriname is Dutch. South Georgia and the Sandwich Islands also have English as the official language but it is not, of course, on the mainland.