What are two unique features of functions defined with a fat arrow as compared to normal function definition? Choose 2 answers
选项：

A:The function generates its own this making it useful for separating the function's scope from its enclosing scope.
B:The function uses the this from the enclosing scope.
C:If the function has a single expression in the function body, the expression will be evaluated and implicitly returned.
D:The function receives an argument that is always in scope, called parentThis, which is the enclosing lexical scope.