Word order in passive sentences with adverbs of time

[Jennifer 49]

When the by-agent is included in a passive sentence, and there is an adverb of time, is there a strict rule for the word order of the adverb of time? I.e.must the adverb of time come at the very end of the sentence (as long as it isn't at the beginning of the sentence)? Or can the position of the by-agent and the adverb of time be switched with no effect on the grammatical correctness of the sentence?

Here are example sentences:

a) The streets are cleaned by city workers every night.
b) The streets are cleaned every night by city workers.


Or should the adverb of time be placed at the beginning of the sentence to avoid the problem of "competing" with the by-agent entirely?

Thanks for your help.

[Nightmare85]

**Neither a teacher nor a native speaker.**

Hello

My personal opinion:
a) The streets are cleaned by city workers every night.
b) The streets are cleaned every night by city workers.

Furthermore, I'm thinking if it wouldn't be better to replace are by get.
The streets get cleaned...

I hope we will get a confirmation by some other members/teachers

Cheers!

[Rover_KE]

a) The streets are cleaned by city workers every night.
b) The streets are cleaned every night by city workers.

Both sentences are correct and grammatical and mean the same.

There is also:

c) Every night the streets are cleaned by city workers.

(Avoid get cleaned.)

Rover

[Nightmare85]

Just an addition.
By using the I did not want to say number to was wrong

Yes, Jennifer has already mentioned your c) sentence.

Cheers!