The word you are looking for is mutter. The Oxford Living Dictionary has, as a noun:

A barely audible utterance, especially one expressing dissatisfaction or irritation.

Is there an example for the verb

behind the verb: Back-benchers were muttering about the next reshuffle. I want to vote for the right to vote. And as an example for the verb – you could take to social media a sentence with this verb:

Why is it that?

The word you are looking for is mutter. The Oxford Living Dictionary has, as a noun:

A barely audible utterance, especially one expressing dissatisfaction or irritation.

Is there an example for the verb

behind the verb: Back-benchers were muttering about the next reshuffle. I want to vote for the right to vote. And as an example for the verb – you could take to social media a sentence with this verb:

Why is it that?

A common idiom for this situation is fresh pair of eyes (a fresh

pair of eyes).

A common idiom for this situation is fresh pair of eyes (a fresh

pair of eyes).