action vs act

[Min Kin]

English Language Tests, Intermediate level

ESL/EFL Test #58 "Lots of Pieces", question 5

The burglar also had an assistant with him who clearly didn't want to get involved and have a piece of the ......... and fled.

(a) activity
(b) action
(c) act
(d) acting

English Language Tests, Intermediate level

ESL/EFL Test #58 "Lots of Pieces", answer 5

The burglar also had an assistant with him who clearly didn't want to get involved and have a piece of the action and fled.

Correct answer: (b) action

Your answer was: incorrect
The burglar also had an assistant with him who clearly didn't want to get involved and have a piece of the act and fled.
_________________________

I didn`t understand the meaning ot this sentence and usage of action - why not act?

Min Kin

[Mister Micawber]

.
The idiom is 'a piece of the action' = (Informal) a share of the proceeds or profits: 'Cut me in for a piece of the action'.
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber