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 dog lays next to a bag on a couch'. Reverse all words of length '4' in the given sentence.
Example Output: a dog syal txen to a bag on a couch

Example Input: Sentence: 'a bird looks around as it sits on a wire'. Reverse all words of length '4' in the given sentence.
Example Output: a drib looks around as it stis on a eriw

Example Input: Sentence: 'a person that is standing on surfboard in the water'. Reverse all words of length '3' in the given sentence.
Example Output:
a person that is standing on surfboard in eht water