not know B from a battledore

To be really stupid, or perhaps illiterate. The now-outdated term "battledore" was often used in reference to a children's primer. It was likely used in this phrase simply for the sake of alliteration. How do you manage to burn pasta? It's like you don't know B from a battledore.

Common Names:

Name	Pronounced	Usage
Donagh	-	Irish
Amse	-	Frisian
Fulbert	-	French, Ancient Germanic
Anne	[æn]
Arrow	['ærəu]
Dania (2)	-	Arabic