Define syntax and semantics.

What three extensions are common to most EBNFs?

Write a grammar for the language consisting of strings that have $n$ copies of the letter a followed by the same number of copies of the letter $b,$ where $n>0.$ For example, the strings ab$,$ aaaabbbb, and aaaaaaabbbbbbbb are in the language but a$,$ abb, ba$,$ and aaabb are not.

Convert the following EBNF to BNF: $SA\{bA\}Aa[b]A$

Describe, in English, the language defined by the following grammar:

$$

$a|a|$

$b|b|$

$c|c|ab$

$b|b|$

$a|a|$