meaning of "roll up our sleeves"

[Editha]

English Idioms and Expressions, Advanced Level

ESL/EFL Test #46 "Clothing Idioms (2)", question 7

Well, it's time to roll up our sleeves!

(a) work hard
(b) wash our clothes
(c) eat

English Idioms and Expressions, Advanced Level

ESL/EFL Test #46 "Clothing Idioms (2)", answer 7

Well, it's time to work hard!

Correct answer: (a) work hard
_________________________

I do not know "rool up our sleeves" mean?

Editha

[Lost_Soul]

When you want to work really hard, like there's no tomorrow I'd say, you usually roll up your sleeves in order not to stain your clothes.

It's time we rolled up our sleeves if we want to speak English