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 The now-outdated term "battledore" was often used in reference to a children's primer.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
Ambrozije	-	Croatian (Rare)
Desmond	DEZ-mənd	English, Irish
Benayahu	-	Biblical Hebrew
Dakarai	-	Southern African, Shona
Monica	MAHN-i-kə (English)	English, Italian, Portuguese, Romanian, Late Roman
MÁEl Sechnaill	-	Ancient Irish