What would you add if the root word is a by itself?

It's hard to say what you might add to "a" without more context! "A" can be many things, depending on what you're talking about:

* A letter: You could add other letters to form words like "at", "an", "am", "ago", etc.

* An article: You could add nouns to create phrases like "a car", "a dog", "a house", etc.

* A prefix: You could add it to other words to change their meaning, like "asleep", "ahead", "away", etc.

* A part of a longer word: "A" could be a part of a word like "again", "always", "already", etc.

Could you give me more information about what you mean by "a by itself"? What kind of word are you trying to create? This will help me understand what you want to add!