What double consonant rule applies when you add?

The double consonant rule applies when you add a suffix that begins with a vowel to a word that ends in a single consonant preceded by a single vowel.

Here's a breakdown:

1. Single Consonant: The word must end in a single consonant, not a double consonant.

2. Preceded by a Single Vowel: The consonant must be preceded by a single vowel, not a double vowel.

3. Suffix Begins with a Vowel: The suffix you are adding must begin with a vowel.

Examples:

* "stop" + "ing" = "stopping"

* "swim" + "er" = "swimmer"

* "run" + "ing" = "running"

Exceptions:

* "x" is always doubled: "box" + "es" = "boxes"

* "w" and "y" are not doubled: "saw" + "ing" = "sawing", "play" + "er" = "player"

Remember, these are just guidelines, and there are always exceptions. The best way to learn the rule is to practice!