Final answer:
A regular expression can be used to match any four-letter word that begins with an 'f'.
Step-by-step explanation:
A regular expression can be used to match any four-letter word that begins with an f. The regular expression pattern to achieve this is ^f[a-z]{3}$. Let's break down this pattern:
- ^ - Specifies the start of the word
- f - Matches the letter f exactly
- [a-z] - Matches any lowercase letter
- {3} - Specifies that the previous character (defined in the square brackets) should match exactly three times
- $ - Specifies the end of the word
Using this regular expression pattern, examples of four-letter words that would match include flaw, face, fact, and fuel. Any word that doesn't begin with an f or that has a different length would not match the pattern.