I
was always a bit slow on the uptake as a kid, so
school was never my favorite place to be.
Uptake,
ahora obsoleto como verbo, ha significado comprender
desde comienzos del siglo XIX, viniendo del verbo to
take up.
Entenderemos mejor
este idiom si imaginamos que estamos aprendiendo algo de
un libro. En ese caso cogemos (take) la
información de sus páginas hacia arriba (up),
hacia nuestro cerebro. En este caso, ese proceso es
lento, existiendo por ello problemas de comprensión.
Otro idiom con el
mismo significado es to be slow on the draw
The origin of the phrase is unclear. It might have
originated in the early 1700s in other forms, but
was not very popular. It gained popularity in the
mid 1900s, after a stage show called "Out On The
Town" was performed in 1944 and a film by the same
name came out in 1949.
https://www.theidioms.com/out-on-the-town/