Try and make a variable named class and see what happens — You’ll notice you get an error.
This lets you used reserved words as variable names.
Unrelated, you’ll also notice strings prefixed with @ as well — This isn’t the same thing…
string says = @"He said ""This literal string lets me use \ normally
and even line breaks"".";
This allows you to use ‘literal’ value of the string, meaning you can have new lines or characters without escapes, etc…