Which of the following is NOT a distinctive feature of human language

单项选择题________is the capital city of Canada.

单项选择题Syntax is the study of_______.

单项选择题The President during the American Civil War was______.

单项选择题William Sidney Porter known as O. Henry, is most famous for_______.

单项选择题What essentially distinguishes semantics and pragmatics is the notion of______.