meaning of "He spilled water on my paperwork"

[Boddy]

English Grammar Tests, Elementary Level

ESL/EFL Test #45 "Basic English Expressions", question 2

Valerie spilled water ......... my paperwork.

(a) in
(b) on
(c) at
(d) across

English Grammar Tests, Elementary Level

ESL/EFL Test #45 "Basic English Expressions", answer 2

Valerie spilled water on my paperwork.

Correct answer: (b) on
_________________________

What does the whole sentence mean?

Thanks.
Boddy

[Conchita]

Valerie spilled water on my paperwork.

The sentence means that Valerie poured water out of a container (by mistake) on the piece(s) of paper I was working on.