In this task, you need to reverse all words of a given length in the sentence. The number of letters in a word determine its length. For example, the length of the word "apple" is 5.

Example Input: Sentence: 'a couple of women sitting on a bench with a dog'. Reverse all words of length '4' in the given sentence.
Example Output: a couple of women sitting on a bench htiw a dog

Example Input: Sentence: 'a large flock of birds fly through the sky'. Reverse all words of length '3' in the given sentence.
Example Output: a large flock of birds ylf through eht yks

Example Input: Sentence: 'a man wearing glasses holding up a cell phone to his ear'. Reverse all words of length '7' in the given sentence.
Example Output:
a man gniraew sessalg gnidloh up a cell phone to his ear